Drop outs under specific conditions

Hi all, 

I know drop outs are a commonly discussed issue, but I'm posting this in case anybody has had the same issue.

I've had these Vector 3s for about a year. I started getting issues with the long spindle screw in the left hand side working its way loose while riding - I put a little bit of blue threadlock on it and screwed it back in. Don't know if that's related.

When I clip in, I get a drop out. It usually takes a few minutes of riding for it to reestablish a connection with the head unit (Edge 520) and start working again.

If I do a short, hard sprint (hard for me = approx 900 watts), again power drops out. Sometimes when it comes back after a sprint I get huge power spikes up into the several thousands range.

Additionally, I occasionally get drop outs if I go over a pothole or bump.

I was getting right sensor missing messages before, and I replaced the right door cover with a new one which seemed to fix the issue. I don't have a new left side door cover, it's still the original.

It sounds like something related to pressure on the pedal, but I can't be sure.

Has anybody seen this before?

Cheers