Interestingly, unlike in Europe and North America, I have seen that Japan in particular has marketed most of its medium and high wattage high pressure sodium lamps and metal halide lamps as direct retrofit lamps for mercury vapor ballasts, which certainly helps reduce the likelihood of mismatching between lamps and ballasts as long as the wattage matches or is close enough such as 400W quartz metal halide retrofit lamps being designed for 400W mercury vapor ballasts or 360W high pressure sodium retrofit lamps designed for 400W mercury vapor ballasts.

Even though the information I explained above is largely true for many Japanese HID lamps, I am also aware of some Japanese high pressure sodium lamps and metal halide lamps being designed for dedicated ballasts. Dedicated ballast high pressure sodium and metal halide lamps tend to be more of a thing for low wattage lamps and sometimes for high wattage quartz metal halide lamps sold there. I have read about dedicated ballast medium wattage high pressure sodium and metal halide lamps being sold in Japan, but they tend to be less common.

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...

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 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.

  So the Guideway is the only roadway model left that's sold in the US?? That's extremely shocking and disappointing. Cree is on a downfall now that nearly half of their lineup has been discontinued. They need to release more new models quickly before they lose sales and pull out of the US completely...

For household use, the last of the made in USA Sylvania bulbs. Not only do they have a short life span, but they have a design flaw that makes them dangerous. The envelope with the LED filament arrays is glued to the base. That glue is right where the heat from the driver and the heat from the LEDs meet which causes the glue to fail. These will then fall out of the fixture leaving only the driver and base portion behind. So if used in an open fixture, they can fall right out of it and shatter on the floor. I'm lucky that I haven't had any shatter (they bounced instead) but I've had a couple fall out. I've removed them all from use.

The Traveyo is also no longer available in the USA.

The RSW Series has now been taken down... Makes me wonder if that's discontinued now, too.

 Every retrofit I've seen has had the original gear left in place with the wires cut (usually really short) .

 This goes for the 400w MV to 150w HPS retrofitted cobras I got from a hotel/chinese resturant , The 1000w MH shoebox to LED (same place   and my 700w MV OV-50 which was retrofitted to a giant CFL.

You have an advantage to live in Europe, I don't believe all stocks around already are depleted. Look at some electrical distributors, I'd look in Germany and in some oddball places like Estonia, or so...