This was a variety of weapons. I first noticed it with some fighters I was salvaging parts from. They had 1 extra of some of their weapons. (i.e. I was salvaging a Kirghiz C and I noticed after I salvaged the initial UAC20, 2 LPL, ER SL, 2 ER PPC, 2 ER LL [and they were all marked off in red for the unit display] there was still a UAC20, LPL, ER SL, ER PPC and ER LL to salvage. )
And then for 'Mechs: I had a Firestarter that had 7 double heat sinks that needed removed (even though it didn't have any HS outside the engine and they couldn't be replaced once removed, despite showing as missing) and then later, a mech with 2 small lasers in an arm (and none else where) had everything repaired except those, yet it reported 3 needing replaced.
I've also noticed that at least one campaign file I'm running has been ballooning on nearly every save, despite minimal changes/unit growth (i.e. 3 mbs to 4.5, 6, 7.5, etc) it is up to 11-12 mbs now but it is far smaller than other campaigns I have that don't take up as much space.