I had 30~seconds left on a Damage Elixir(30% 45min one i believe) and used another of the same while outside rahab portal. It applied with msg and icon but i noticed the after one run it was back to seconds left.

I tried the process again but this time remapping(To Windmoore)with the map instead of using the port after killing Rahab and the elix stuck around(No idea if any of that matters).

TIA