New to power-based training: 3 months in, FTP dropping/fluctuating

Correct. I didn’t have a Quarq previously, so I just used the Kickr. After I got a Quarq I did some dual measurments to confirm they are in line (average difference being 3-5 watt with the Quarq measuring lower. With that I did a month of training which went well, although the VO2max was very painful and hard to complete. The sub-treshhold all was easy, also the 30 minute blocks (everything with powermatch).
Outside I only had the Quarq ofcourse, and performance was much better as inside, but that is to be expected I understand.
The test yesterday was with Quarq as PM and with powermatch, so basically how I have been training for the last month. But my performance was very poor, or at least much below expectation, as I am feeling much stronger as a month back (which is to be expected since I only started training recently and improvements are big in the beginning).