Thanks for digging into this. Yes, I suspected that delayed results going to the subsequent commands would crash (e.g. expecting a number on Cmd1, which times out, then Cmd3 gets it, and things go haywire.
So yes, buffer clearing is a good idea, but how long would one wait? SWS has a default of 200 ms timeout, plus the time a command takes on OnStep. It varies. Maybe 250 ms minimum timeout is safe? I don't know.
Yes, if you bypass the Wemos you will get different results. The thing is, the Wemos runs new software (SWS) which has some internal processing, and is a bit different from the addon. So what you are seeing is probably buried in SWS somewhere.
Regarding the rotator, are you testing with the conditional GX98 code? If not, then yes, the :r commands will take a long time and cause problems.
I don't have much to add here, so will wait until the experts finish their analysis.
In the meantime, should Alain push the small GX98 patch to Jasem, to prevent having others report the same issue?