I'm early in the game but decided to not go to Concord, instead heading straight east.

As such, I've collected two Power Armor frames, and enough parts to have one full suit.

However, after parking both frames in Sanctuary, I discovered that when I fast travel the suits change parts randomly. I initially had Raider Power Arm and Leg on one suit. When I returned, they had changed to T-45 parts, but the helmet has disappeared. To avoid the glitch, I stripped the parts off the armor and stored them.

Now, when I fast travel, random Power Armor parts spawn on the empty Power Frames.

I had two empty frames when I left Sanctuary and when I returned I had two nearly full armors.