When...
- crewmates are assigned with supplying systems (like say, a railgun or an engine)
- they are also assigned to a capacitor
- they have higher priority on the capacitor
- and said capacitor is not assigned
... the crew take energy to the capacitor (as to supply the said system) and put it back to the capacitor instead of moving the battery to the system (as to supply the capacitor), and that repetitively.
Honestly, found about it by chance during my tests. I forgot to lower the capacitor's priority in my crew role AND to reassign the capacitors after moving them, and I noticed it with the Oc Capacitor catching fire due to said actions. In fact, it can even be ignored as it is more of an error of crew priority & capacitor assignment than anything else.