Comment 6 for bug 1838261

Hey!
I also came across an identical error scenario as the op!
Selecting a trace all of a sudden triggered a never-seen-before warning stating:
"Unexpected BOARD::MarkTrace: multiple pad_on_start"
I found this thread while looking for similar experiences, and motivated by this thread I tried removing a via that I had placed on top of a measuring point.
Removing the via got rid of the error message for me.
See the attached screenshots to see the scenario where the error was produced.

Interestingly enough, when I now try to replicate the issue by adding a new via to where it used be before removing it, I can't replicate the error message.
Also, I also had other places on my board design where an identical measuring point was pierced by an identical via, and I wasn't able to reproduce the error there either.

If I re-counter the issue again in a way that I can continuously reproduce it I'll try to provide the board-file to help solve the case!