I am not sure, but it appears that the input from svkbd at the xdm login is "lingering" after login. This means, whenever you open something after logging in, be it the appmenu or a terminal or whatever, it's repeatedly hitting enter. So if you open the appmenu, your first userscript will be run, etc.
The way to stop this is to bring up svkbd and hit a few buttons, and then it's back to normal. Not a huge problem, since it's only at first login and it's easy to prevent it from going haywire, but still annoying.
I can reproduce this. If you start a terminal from xinit, it will spam newlines.
Pretty big deal IMO because I just tried to make LastPass ask for the master password on boot which fails because it spams enter and tries to login with empty passwords..
It'll happen even without an xinit file. If you bring up svkbd and hit some keys before doing literally anything else, it won't happen. If you bring up the menu or open a terminal etc. without opening svkbd after a fresh login, then whatever you open will be spammed with the enter key. This is in Void, but I can't imagine that causing any issues of this type.
Oh wait ! Another issue was double causing mine !
This actually solves the issue :D
According to ~proycon this has been fixed.
"svkbd was killed with -9 from sxmo-xdm-config so it didn't get to do cleanup (keyrelease)"