Client (mini) boxes go out of sync with DVR

[LL110]

I have had an ongoing problem with the client boxes going out of sync with the main DVR. I have 2 client boxes. When this happens (randomly every few weeks) the pause/fast forward/ and rewind functions do not work properly. I’m able to fix this by rebooting the main DVR and then the client boxes, but it’s a temporary fix. This started with my original Fios set up (wired) and after multiple calls, tech visits and replacement of all the units twice the problem persisted. Thinking the issue was the internal wiring in my apartment (I live in a loft, DVR downstairs and client boxes one floor up), I was advised to go wireless.  The problem has continued with my Fios one wireless set up. 

My ONT is not in my loft ( it’s 2 floors below ) and the last tech thought the problem was the long coax distance. I have since added a coax amp and and a wireless extender, which I placed next to the mini. No luck. 

Any ideas??