Problem after several minutes of coasting - has anyone seen this before?

Today I did a long climb, followed by a long descent, where I did a few minutes of coasting without pedaling - power was plugged in. After that the trainer lost resistance and made just rattling noises in any ride I tried. It sounded so bad, that I thought the trainer was broken, although just a few minutes before during the climb it worked just fine. There were no unusual things happening during the descent, nor was there any force applied 

Checked the belt, but that was fine, and all of a sudden it worked again - probably because I disconnected power for a few minutes beforehand. Firmware is 0.43.

Are there any simiar experiences out there?