Since nobody has responded I’ll just share my experience. I don’t have a dehydrator. I find thyme dries fine just leaving it on the kitchen counter.

I don't pay any attention to what instructions say when dehydrating other than what temperature various things are supposed to be dried at. Herbs I dry at 95F.

I just check things every 6-8 hours to see if they have dried completely and to rotate the trays. If I am going to bed I usually turn off the dehydrator until morning.

I find that it helps to take the leaves off the stems - which have to dry too and take longer.

Thanks for the comments! In my environment thyme simply will not dry completely on the kitchen counter. As for taking the leaves off the stems, I think I will attempt that next thyme. (Har har)

Is there a good way to tell when the thyme is correctly dry? I have heard that crumbling is a good test, but occasionally when I gather it into my spice jar I will notice a green smell, even when the leaves powder easily.

Thought of this post when I came across this blog entry about dehydrated thyme. https://wellpreserved.ca/trick-storing-dried-thyme/