In Cloudrest, the "Shed Hoarfrost" synergy is lower on the priority list than the synergy to enter the portal.
Yes, if you have the hoarfrost you shouldn't go near the portal to drop it anyway, but if you're in a transition, it's not hard to make the mistake of dropping it on the way and being by the portal.
Currently:
1.) If you are a portal runner trying to drop the hoarfrost before you go through the portal, you can bring it down which is never good.
2.) If you are trying to stay upstairs and happen to be near a portal, you take the ice downstairs. In this situation, you end up with ice downstairs, and an extra person in portal which can lead to a wipe if it is at a bad time (like during meteors when Galenwe is out).
3.) You're a portal runner, but it's not your portal. In this situation, you just die, then ice still goes loose. Now someone else is getting ice, and they have to kill your shade and ressurect you.
All of this could be avoided if the Hoarfrost Synergy had priority over portals so you drop it and move away.