Deleting agenda item causes random removal of role assignment

Club 4798.
OK, I'm sure it's not random, but there does appear to be a bug in the agenda editor. When I delete an agenda item, such as "Speaker #3", at least one role assignment disappears somewhere else on the agenda. At first, I thought it was my imagination, but it has happened about 5 times now. It should be easily reproduceable. Assign roles to most of the agenda items, then delete an (unassigned) agenda item. Then, see if all the other role assignments are still intact.