Replying to stefan.tauner@…:
The exception told me to append to this ticket, so i am reopening it...
Thanks. Despite the (misleading) error message, this error is hardly related to this ticket but seems to be another case of #7847 as the incriminated node has been deleted (http://www.openstreetmap.org/browse/node/1779819403).
I'm closing this ticket and reopening #7847 instead. If you're able to reproduce this bug (right now I don't see how to reproduce it myself), I'd like the following elements as attached elements in #7847:
- The two layers you were trying to merge, if possible
- If not, the resulting layer
- A screenshot of the strange artifacts you were talking about
Let's talk on the other ticket :)