You're receiving a Yellow, meaning the far end equipment is seeing no signal. You loop it up and after releasing it clears, which to me means the far end equipment will sync to itself and releasing the loop causes your equipment to re-sync to the far end. I'm betting if you unplug from the NID wait a few seconds and plug it back in it will also re-sync. The best way to trouble shoot this would be to see if there is a signal from your equipment when you see the yellow by bridging into the circuit or putting a monitor on it. If you see a signal yet still receive the yellow the trouble is beyond you, a monitor could also be put at the NID.

I assume the LEC has remote testing capabilities on this, they could also see what signals they are getting when you see the yellow. Of course that takes the cooperation of the LEC.

Retired phone dude