Yes it is true that V Caps take several 100 hours to break in (I have CuTF, TFTF and OIMP). You should have built a jig and burned them in on your work bench before installing them, you could always remove them, burn them in and then re-install.
A jig can be as simple as taking an old receiver, or similar, connecting a 4 or 8 ohm power resistor (I use 50 watt) in series with the capacitor in question, or several wired in parallel. Turn it on and increase the 'volume' over time monitoring the temperature of the resistor and output devices/heatsinks, as a rule of thumb, if you can comfortably touch the resistor and output devices/heatsinks you should be OK.