Sounds like a bad relay I had back in the day,
but that was 25+ years ago & I have half-zymers now & recall half the stuff half the time, hopefully alternating so I get it all coming back to me at some point!
If you have another TS relay, try swapping it & see it that solves it.
Otherwise when you come over, we could pull mine out of my 914 to try to see if that's it, but when they're intermittent problems it's dang hard to trace! In that case wait until they're doing it & call me & drive it over here & we'll swap it then.
Remind me to check the red racer's fuse panel to see if there's an "extra" one in there, when you come over this eve.