Portal specific issues

When you hold a object and let it pass through a portal without also going through, the object/prop tries to fly back in a straight line to where the player is. this happens more notably when holding something with gravgun.

There's also a lot of portal maps issues but that's out of question for now since it lacks EDT to begin with.

Also, from @Balimbanana

specifically on dedicated servers it seems the max velocity you can travel through a portal is directly affected by the clients framerate.

To test, put a portal directly above and below you, so you fall endlessly. Set fps_max 30 and you will almost halt at every portal change, then set it to 60 or other settings.