When you use a rank token it resets the idle animation (very minor bug lol)
Video:
This is not of concern lol
If I'm not mistaken it's always been like this since Jiggmin introduced rank tokens.
This is the local character's animation restarting due to the client receiving data from the server that prompts a refresh (e.g. new part/purchase, guild name, etc). Some will say it's a feature! Others will say it's a bug. Oh well. I say maybe it's Maybelline.