@cheesej Hiya :) That's a 270uH power inductor. If there's actual damage to the windings on it that could cause issues.
The only time I've seen similar when the battery was fine is dodgy caps on the balance IC.
Cell voltages can report incorrectly if any of the caps around the balance chip at the other end of the pcb are slightly detached or faulty. Common to do when unplugging the XT60 and bumping one.
Might be worth giving this post a lookover to see if your board is doing similar if the inductor doesn't solve the issue.
https://owforum.co.uk/topic/403/xr-overcharged-cell-that-isn-t-after-battery-upgrade-repaired