During recording you cannot use “undo” or “redo”.
You can do all kind of edits, but you cannot undo them.
An example where this gets unintuitive:
If you make an edit during recording and you hit “undo” afterwards, you will always delete the recorded event first and then be able to undo the edit by hitting “undo” again.
That’s how it’s designed.
At first it seems so, but this seems to be more like an issue they did not want to fix, than by design.
You subjective analysis has been registered. 
You think?
If it is by design, then why am I able to do all kind of edits during recording, but unable to undo them?
And how do I undo an edit I did during recording afterwards and at the same time keep the recorded event?
Cause now, if you hit “undo” afterwards, the recorded event gets always deleted first.
Then I guess I should not do any edits when recording? Then my next question would be: why it is even possible to edit things on the go then? 