So this morning I had to do some mandatory work to The Genesis. (Had to empty out my oil catch cans, rearrange one oil catch can, and attach a new fuel
hose to that same catch can as well. Also had to refill the coolant in my radiator and reservoir tank.)
This required me to turn on my six Metal Halide 50w Wallpacks. (USA made GE HALARC 50w QMH.) When I turned them on, pretty much all of them (except for
the lone Caster 50w QMH) flashed violent reddish or violent orange during warm up, which is rare. Normally only one or two of them do this.
During installation of my new fuel hose to the oil catch can, I had to use a hair dryer to help expand that rubber hose, which... required me to shut off
my Metal Halides, since that hair dryer uses a lot of watts/amps. (Only one receptacle is in that garage.) After I was done, I unplugged the hair dryer
and fired up my Metal Halides again... same thing. Lots of brilliant reddish/orange flashing during warm up time.
After I was done with everything, I shut down the garage and went into my apartment. In my bedroom, I turned on my 20w CMH track lights, and my two GE
self ballasted PAR38's.
Although my 20w track lights warmed up without flashing, both my GE self ballasted PAR38's violently pink flashed, and one of them shut off during this,
and restriked a few minutes later.
So... what's up? Why so many brilliant flashes? This may be a dumb question, but does this have anything to do with environmental conditions?

Must be some kind of environmental thing, or due to the current conditions of the electrical grid. I have noticed the same, as well as how long preheat fluorescents take to start. When I start more than one at once, most times they can take a long time or a short time, but all are either fast or slow. They are especially slow in the first hour after a somewhat long power outage.

As for a flash that extinguishes MH lamps during warmup, I’ve only had it on a new GE 39w G12 and after about 30 starts, it now rarely flashes at all.

I forgot to mention that one of my USA made GE HALARC 50w QMH lamps in my garage has also shut off during an orange flash, as well as one of my Sylvania 50w QMH, (back when I had my Sylvania 50w lamps in my wallpacks) during an orange flash. Makes me wonder why this happens. So, both the magnetic 50w wallpacks and electronic GE Self Ballasted PAR38's have done this at some point in time.
Very interesting seeing those brilliant orange flashes in my garage Metal Halides, far more interesting than the Par38's pink flashes... but so weird seeing that the Par38's and the Wallpacks are doing these brilliant flashes so often today.

I think the lamp position in your wallpack is favorable for the flashes (salts becoming separated when condensing after shut down, then evaporating in an uneven manner when fired back up), it just took some time to redistribute that way.

Could this also be the same for those electronic ballasted CMH's? All of those are being used as up-lighting, vertically positioned as well.
... so the MH's being vertically positioned can at times increase those flashes?
Here soon I will be taking out those 50w GE HALARC lamps, switching back to the Sylvania 50w ones for a little while, just to extend the life
of those GE lamps. (Those are the best QMH's so far in my collection, easily.)

I observed such colored flashes first with Osram HCI-TS 70W, burned horizontally (the only rated position for this format), started to appear really few cycles after new.
If I rotated the lamp, the flashing changed for few cycles a bit, but then returned to the same as before ("same" being very relative word here, as the flashes are really quite random).
To me this is rather normal and expected behavior, once the fill is a mixture of various components. Most components have very strong tendency to form crystals when solidifying. And crystallization just tends to separate them apart. The effect is normally used as a way to separate (clean) materials from impurities - formed crystals are always cleaner than the melt they are formed from, as impurities most often do not fit well into the lattice...