You definitely can! There is an edit button next to the event:
If there is an issue with saving edits, that’s another matter. At least for me it works normally, just tried.
This is unfortunately not an easy fix as we use a third-party editor on the form. The easiest way to achieve this is to use “paste without formatting” option from your operating system (at least macOS has this, I assume others as well) OR you paste the text first into a text editor that doesn’t support formatting, and then copy it from there.
The current playlist functionality only works with DJ-software exports, it has nothing to do with this. But it’s on a pretty high prio to get a freeform text pasted as playlists after the set – probably with the next update!
Also, in an unrelated note, I noticed that one of your events was cancelled due to the date being wrong. There was an issue with user profile editing fixed just yesterday, please doublecheck that your timezone information is correct in your user profile! (Here: https://slipmat.io/account/ )