I've started seeing a twitch like prop wash,  seems to occur in  about 3 sec intervals, then stops.    I've never noticed it before,  and I fly alot,  so I don't think it's propwash.   

Hello there BarnSwallow. I am sorry for the trouble this has caused and thank you for reaching out. May we please know before having this issue did your DJI FPV had a hard landing or a crash before? In addition, kindly please try to check the propellers of your DJI Drone as well for scratches or damages for us to be able to isolate the said issue? Thank you.

Not 100% sure but does appear related to the props.  I'd try a new set of props and see if that alleviates the issue.  Hope you can resolve the issue soon.