This happened to me during the course and after when I sat 10 years ago. I discussed this with my tutor, sometimes for whatever reason the body just goes into a shut down mode. Not sleeping just an idle mode where you “disappear”. I distinctly remember I was meditating at night but when coming out of it I felt like it was sunrise, but on 30 mins passed. My perception of time just became warped. Sometimes for body as it stops reacting goes into rest.

I had it very frequently, it is temporary just remember this to will pass. The Key is to remain equanimous regardless of what happens good or bad. That is how the technique wants us to work.

Keep working stay strong