has anybody else noticed this about flac audio?

If you read up on FLAC, you will discover that all the hard work is done on the compression side. Decompressing the FLAC file doesn’t really change the CPU load much even comparing level 0 to level 8. Yes, even FLAC level 0 is compressed. There is uncompressed FLAC but it appears you that has not been tried here based on what I have read. 
The DAC never sees the compressed music data. The CPU load is not all that different at any level of compression so what is asserted by the OP here is really far out there. I have never heard any difference in sound quality in FLAC compression levels. 

@danvignau 

If you use a lossless compression format to store a file and compare that to a format like does not compress like WAV, the data in the files is bit for bit identical. Only the wrapper has changed. Again, the DAC gets the same exact data, bit for bit, using either type of lossless format. In other words, you are getting 100% of the music either way....

@guitarsam
   try out the foobar abx comparator to randomize the comparison between the versions.
http://wiki.hydrogenaud.io/index.php?title=Foobar2000:Components_0.9/foo_abx
See if you can consistently pick out which file is which. I only got 9/16 right which is pretty much close to a random coin flip.

Maybe I was not clear enough.  I agree that their may be streaming formats that play back exactly what is sent, but it is still compressed before sending.  That is why I favor D to D LP's, and even it is mixed down in the console before the cutting head, even if it is mainly for the the RIAA curve.  I would love to be proven wrong, then I would buy a streamer, but so far, people who have streamers I have heard do not have systems that show these flaws.  Garbage into the internet; garbage out.  I would love to hear streamed music that is beyond excellent, but even the stereo stores have not demonstrated it sufficiently for me.   Close is certainly not better, and if it isn't better, what good is it?  We don't all just want the algorithms used to suggest music for the masses to  define our listening experience.

It is not compressed.

Qobuz is better than anything on a CD when truly hi-res, but if you have a really good CD quality stream, you are not going to notice anyway. Either way, Qoboz, Tidal CD quality (not MQA), etc. are all not compressed.

Given this statement, you are pretty much saying that even when you don't hear a difference, there is a difference, so how will you know either way?

people who have streamers I have heard do not have systems that show these flaws.