I'm late to the party too....
I don't think it's necessary to wait "6 months" if the tank is stable. I've seen some tanks that weren't stable after 6 months - but that is a whole other post about 'user error'.
Usually when an anemone is placed into a different system, it will slowly purge all the water out of its system, and take up water from the new system. I've heard it called 'water changing' and that's an appropriate description. They'll contort and fuss and during that time, they'll shrivel up, partially reinflate - which is also the way they move around.
Just relax, let it be, keep an eye it doesn't wander into trouble like a a filter or powerhead intake, and let it be.
The more you poke it about, the longer it will take to settle.
Jenn