Thanks for sharing this. I'm currently measuring the BPSK beacon frequency 24/7 for the next few days and posting updates on my Twitter ( EA4GPZ). Unfortunately I lost last night's worth of measurements due to a network problem. I find this weird wiggles quite interesting, since I haven't seen them before, and certainly they weren't present the last time that I made precise measurements, back in October 2019.
Mario DL5MLO tells me that the GPSDO at Bochum is not to be trusted 100%, since it is reporting some error (control voltage at limit) and people can't currently get in Bochum to check, due to the lockdown. I might also measure the engineering beacon at 10706 MHz to rule out anything having to do with the Bochum beacon. I think that beacon can be received in Madrid, since we're on the edge of the MENA beam, but it's been a while since the last time I tuned to it. Another idea is to put up a constant carrier myself through the NB transponder (with the appropriate CW id nearby, of course).
Interestingly it seems that the wiggles start at eclipse and half an orbit later. This is eclipse season, so the sun angle with respect to the orbital plane is small (this is the reason why there is eclipse in the first place). Depending on how the satellite attitude is controlled to aim its solar panels to the sun, it might need to do large yaw rates at eclipse and half an orbit later. The wiggles may or may not be related to this. We'll see how this evolves as the sun angle continues increasing and eclipses disappear (last night it was the last eclipse of the season).