Haha, gotta love it, so two wrongs kinda make it right for now - it does fire up like all 8 glowplugs are working again tho, before it'd hesitate firing even after two complete auto-cycles of the glowplugs, now it fires right up! Also duration of having the glows active does vary with ambient temperature, just like it should, so it really don't act like there's anything wrong with it... Oh well, I'll check on the ground and then just keep running it as is, when it goes stupid again I'll put the new glows in.
One thing tho - the glows fixing themselves just so happens to coincide with me turning the injection pump down and re-timing it. Come to think of it, them "failing" also coincided with me turning the pump quite up about a month ago... A bit too much of coinciding there for my liking - is it possible the extra fuel somehow fouled the rearmost glows, while the much cleaner burn for the last road trip cleaned them up, or something of that sort?