Bug: Splitting a single token into multiple tokens fails

I had the following frontend bug occur in current dev, but I did not manage to reproduce it unfortunately.

I transcribed "Jens Spahn's Credit Score is Very Good" from cccamp23. At timestamp 40:20 whisper recognized "die überlegen jetzt an ner Lösung" as "die überlegen jetzt Analösung". I selected the "Anal" (sorry) in "Analösung" to edit that token and typed "an ner L", but the UI would only edit the first letter so the "an ner " was just completely lost.

I was unable to reproduce the bug with other words in several attempts, but maybe somebody else had this happen and had better luck or you have an idea how this could happen in the editor.