Hi Anja,
You're right - the note is not yet published for some reason.
I've asked the colleagues to look into this.
Basically, the reason for the error is that in the newer version has more strict validations on the process model.
If there are boundary events with no activities attached, the build will fail now whereas it worked fine with the older version.
If you can't or don't want to change the process model(s) manually you can create a OSS message and ask SAP support how to fix the problem with a script.
Regards,
Christian