sorry that I had not responded earlier. I had to solve a lot of other system problems and this here had a workaround, therefore this topic had been on a low priority on my side.
At least in the current 5.35.0 release I do no longer have the problem.
And yes we do have the bleve enabled with EnableAutocomplete set to true.
Perhaps it was a problem in the index. I did recreate the index for bleve a couple of days ago.
But I had not checked at that time if the problem had been gone.
I only checked it now and noticed that the problem does no longer exist.