I discovered the following strange behaviour:
Download a way with minimum 4 nodes. (The way needs an OSM-ID otherwise the dialogue won’t pop-up.)
Mark one node and hit “P” to split the way.
Ignore the dialogue.
Mark a second node and hit “P” again.
Accept the suggestion for retaining the ID (2x).
This will create an overlapping section on the 3 ways.
Can somebody check and confirm?