been trying to work AO-91 this morning and the transponder seems shifted down about 2khz from where it should be. doppler correction is on in my software and i double checked the keps are fresh from yesterday. anyone else noticing this or is it just me? using ft-857d with arrow antenna if that matters

Yeah I noticed that too on the 1430z pass. Had to tune down quite a bit to find signals. Could be the satellite is having thermal issues or something with the reference oscillator. These cubesats dont have the most stable freq references to begin with

i always find AO-91 to be a bit drifty compared to the older birds like FO-29. the linear transponders on the Phase 3 sats were much more stable but those cubesats are what we got now i guess. try adjusting your doppler settings manually and see if that helps