Yo-yo effect when pulling with double draft

Although I ride fairly regularly on Zwift, I usually sweep, and avoid double draft rides. Today I was pulling a lot on a ride with double draft on and noticed odd behavior: neither of us changing pace, riders behind me doing about 0.5 w/kg less would regularly shoot past me and then quite quickly fall back again. Pretty often.

After a while I started thinking that this looked like a poor engineer’s implementation of an echelon. Any insights, opinions, similar experiences?

I’m surprised this issue is not mentioned more frequently. I see it on every group ride - to other riders and to me. I’ve quit a few rides because of it as sometimes after a moment at the front I fall back through the pack and then off the back, and unless I put out a few seconds of 5.0+ wkg a gap quickly opens up. Some rides are worse than others.