Occasionally the control board fan was was making more noise than it should. Typically it was on startup and would eventually work itself out.
Contacted support and they needed a video with the ticket number in it. Since the issue was random I was worried about being able to catch the issue. But sure enough next print it happened and had the ticket number prepped on a sticky note ready to go.
They shipped me a new fan and total turn around was about a week and a half. Bit longer than I would like for a printer being down but it did get solved.
Replacing the fan wasn’t too bad. They provided some good directions here: https://wiki.bambulab.com/en/x1/maintenance/replace-mc-board-fan
Only one thing made me read the directions twice. The directions said the fan was glued but its actually using the same double sided tape the new fan came with and pulling it off was a bit unnerving.
Note in he US void stickers are not applicable. So you can safely ignore it with your warranty staying intact. You can read more about these VOID sticker here. Outside the US I suggest reviewing your local laws.
I had not cracked open the Bambu X1C before so was neat to see the inside. Took the opportunity to snap some pictures of model/version number on components if I ever need them.
Fan replacement went off without a hitch.