It's been a few months with no Josm update, as it moved a lot and start to be too old for many plugins, can you please update josm to version 14.07/r7349 please ?
I'll test and give karma if it works
Thank you very much
Link to changes and download : https://josm.openstreetmap.de/wiki/Changelog
The version number in use is still the commit number.
*** This bug has been marked as a duplicate of bug 1125838 ***