it will take them a while to get used to their new home. Just like all Betta's, moving around and being jostled during water changes can be stressful. To help with the stress you can keep the lights off longer and have them on for only a few hours a day. Or if you don't have lights you can drape a towel over the tank to make it darker.
Also 84 degree's isn't necessary, I would actually lower it down to 80 degree's if you can because higher temps are invites for bacterial diseases.
Rembrandt II, Suiché
Leopards: 1:4 Hawkeye, Luna, Astrael, Dorian, Cullen
Gargoyle: Cloudjumper and Toothless