Phasemation Cartridge Compliance or Alignment Issue?

Well now I'm thoroughly confused. I must not have noticed on other records previously, but the woofer pulsing for the outer ~15% of the record is persistent on everything I'm playing ugh.

Turntable hasn’t shifted any. I do have a subwoofer but that pre-dates the cartridge swap. The only other change is a new phono preamp (sutherland little loco mkii). Would the pulsing change over the course of a record if it was a feedback issue? Thats what leads me to believe its an issue with the cart. On the record with the low frequency syth, the tonearm bounces slightly once every rotation and you get an audible sound I can only describe as "tshh". The more I look at the pulsing, it seems to occur once per record rotation across the board. Maybe its an alignment issue?

The spec from MoFi claims the mass is 35g which, based on multiple online sources can't possibly be correct. I was calculating based on a post where someone claims to have contacted MoFi and confirmed the mass is 25.14g in contrast to their specifications.

Some photos of the cartridge - it looks like the cantilever isn't mounted plumb to the head shell. If this is the case, it makes it very hard to align with my protractor. Is it possible that a misalignment could compound the resonance issue I may be having?

https://imgpile.com/p/hvQlA5Z

Troubleshooting this a bit more. I realigned the cartridge and the same behavior is occurring with the woofers. My last thing that I could try was to swap my phono preamp out. I mentioned before that I purchased a Sutherland Mini Loco Mkii at the same time I purchased the phasemation cartridge. This is a current driven phono preamplifier which should pair well with the low impedance output from the phasemation cartridge. My old phono pre is a parasound JC3 jr. This preamp can drive the cart with a little more oomph from my integrated amp.

After making the swap, I would say that the woofer pumping is decreased by about a third of the previous excursion. Again, this behavior lasts for the first 1-2 songs per side. I’m sure the voltage vs current driven typology of the preamps is at play here. If the cartridge and tonearm match is borderline based on what I’m now seeing. The higher system gain mini loco mkii could be exacerbating the problem. I should probably look into the subsonic filter yogiboy recommended. I’m curious now to try another voltage driven phono pre to see if there is any difference related to that. I had been looking at the Pass Labs XP17. Any thoughts on what I might experience changing out the phono pre beyond what I’ve already tried? I like the sound of the phasemation a lot and would prefer not to abandon it if possible since it was such a large investment. I haven’t experienced any tracking issues.

Thanks for the ideas everyone.

I am experiencing a few different types of distortion. In the outer grooves of some records, I've noticed some midrange tones struggling to hold their pitch. For example a guitar string pluck wavering back and forth.

Another form of distortion I've come across is a strange scratching high frequency sound almost like an aggressive tape hiss that occurs rhythmically with each platter rotation. This behavior occurred several times on one record I was listening to in more central grooves as well as the edge of the record. 

I've probably listened to a dozen records over the last few days - each seems to have different sonic behavior and cause differing amounts of woofer pumping. Some records don't cause my woofers to pump at all.

@bill_k  interestingly enough, a few warped records that listened to last night exhibited the least amount of woofer pumping. They actually played better on the side with the edges cupped upwards. I have a record weight that flattens them out on the other side.

@jsalerno277 I want to go through your list here:

1. Warped Records - as stated above, some of my warped records actually exhibited the least amount of woofer pumping. The cupped side exhibited different behavior from the flattened size. I'm confident that I nailed the alignment with my recent reinstallation.
2. Turntable Rumble - I have a 3 year old MoFi Ultradeck. I recently cleaned and relubricated my inverted bearing. I would think there has been no change with my setup here.
3. Turntable Isolation - I have my turntable between my speakers which are about 7 ft apart. The turntable is sitting on a custom steel and wood shelf that I designed. Heavy butcher block shelves are supported on black and blue heavy duty equipment vibration pads you might install under an industrial fan or refrigerator. I don't have any issues with footfall due to this shelf. I don't really have the ability to move my turntable elsewhere. I know that I have a pretty serious hum somewhere in my system that is audible if I don't ground the turntable but absolutely fine otherwise. I have a combined HT and 2 channel setup with a HT bypass integrated amp, processor, TV with eARC, and sub. Sometimes if my cables shift around, I need to position my right channel phono cable just right for the right channel to play. There are plenty of places I could be getting feedback from.
4. Speaker to Stylus Feedback Loop - I never had the distortion or woofer pumping issues with my previous factory fitted MoFi master tracker cartridge. Perhaps the phasemation is more sensitive to feedback?
5. Tonearm Mass/Compliance Mismatch - The online calculator I used has my system resonance at 6.4hz assuming the 25.14g tonearm mass. I have reached out to MoFi to confirm this assumption. I think this is likely what I'm dealing with. Unfortunately I think I will need to swap out the Phasemation cartridge. I don't love the idea of the rumble filter as I doubt it will solve the high frequency distortion I was hearing.

@lewm I hate the antiskate mechanism on my turntable, its inaccurate and unverifiable. You set an O-ring and counter weight on various notches that are supposed to pair with different cartridge weights. I have tried to play records with the setting at each end of the possible spectrum without any noticeable change in behavior.

I'm to the point of searching for a low compliance cart that will work with my current stage phono preamp. I'd rather not abandon the Sutherland if I don't have to. I'm thinking the Ultragold MC could be a good match. It has a proven compliance match and its 12 ohm resistance should function with the Sutherland. The only specification I'm missing is the inductance of the cartridge. Another option I was considering is the Miyajima Shilabe but this is a much more expensive option. I don't really want to go down this rabbit hole again and find I still have mismatch issues.

WAF of new cartridge is much higher than a new turntable, I need to go that route for now.