not meaning to sound negative nor patronizing,
be aware that should you again experience sluggishness or excessive current draw, it might be the WD 40
from my own experience, using electrical contact lube, (and being familiar with WD 40, it may not only leave a residue-as it is designed to do so, but this residue collects the brush gunk, dust etc, -and yo have to do it all again-i know this first hand)
so , if this is the case in awhile, you now know why and how to remove it
fwiw, again from experience, wd 40 has no place in electronics-it is not a lube, it is designed to disperse water and to adhere with a film, to metal, to protect against oxidation-while it will temporarily remove sludge and grunge, simply by drenching it off and away, , make the track nice and remove stuff on it, etc, shortly thereafter, more stuff collects, for the worse-i have followed others recommendatoins for use of WD-40 on the track, only to have later remove every bit with a clean cloth and either meths, LGB smoke fluid, or diluted ammonia to cut the greasy film
of course, your experience my differ from mine