It crashed by sharing from this app: https://play.google.com/store/apps/details?id=de.badischezeitung.smart
There are also other News Apps who using (probably) the same software as Badische Zeitung.
So I think this issue also concerns also other Apps.
I would have a look on Friday, if the issue isn't fixed until then.
The PR (https://github.com/deltachat/deltachat-android/pull/1003) should fix the problem. The actual problem was, that the mentioned app attached a SpannableString instead of a String. Kind of uncommon and "special", but the Delta shouldn't crash. Both cases are working now and I added a check to avoid further crashes, if no valid text is given.
great that you figured that out!