I loved it when she would run up, meow, and then flop on her back. She doesn't do that anymore! Is this a faze cats go through? She's a little over a year. I cuddle her and give her kisses and spoil her rotten! Sniff.....
Cats do things based on reward and learned habits.
Did you by chance change your routine when you got home? For example when she started to greet you at the door, I imagine you gave her pets and whatnot. If you are not consistent with the reward, they come to stop expecting it so they change their behaviour.
Of course it is entirely possible that your kitty doesn't want to be predictable either, so she changed her own routine "just because"