Win 10 Pro 20H2

I often let my "production" PC got to sleep (or manually put it to sleep) with 2 or 3 applications running - email and some other stuff. In the past the Task bar icons for these programs would be in the same order after waking as they were when the computer went to sleep. Later they occasionally (more often then not, but not always) are in a different order after waking. This is obviously not a major problem, but I'd like to understand what is going on.

I have nothing pinned to the task bar so all icons come and go as I start and stop programs with new icons appearing to the right of existing ones.. This behavior has not changed.

I had swapped my "production" and "test" PCs around the time this behavior started so I assume this behavior has always been the case on what had been my test PC, but I can find no settings that are different on the two PCs.

I haven't determined if there is a difference between sleep due to inactivity and manually induced sleep. I also haven't determined whether the behavior is dependent on which applications left running.

Update: It does not on what programs are left running.