None that I can see.
When inputting a really really really long event title in the modal, it simply wraps like all other fields in discourse:
As the event title can already be 255 characters (when it pulls through the Topic Title) any problem with that already exists. But there doesn’t seem to be any. Long titles are truncated with a nice ...:
This is quite a trivial change and addresses a long standing bug / UX issue in the events functionality of the Calendar Plugin. It would of course be better if the Title length limit was the same as the Topic Title length limit.