Yup, I can confirm that in my short tests the D flag seems to be cleared most of the time when first powering on the console. But sometimes it gets set after a few power cycles, and chanches seem to increase if you try a different cart first. It's like if, once the flag is set by the previous cart, its status tend to persist on subsequent powercycles.
Decimal flag seems to start at 0 most of times when you power on the console, but at very random event it could start at 1 and then I got problems.
I tested 4 consoles from different eras and was able to replicate the glitch at least once in all of them.
Yeah, I think anyone would assume it's caused by dirty contacts in the cart slot or the power switch. And the fix is the same too: power cycle the console.
I only noticed this glitch on my hardware like 2 times ever, and I thought was a cartridge connection problem, which was solved by re-inserting the cart (actually power cycling the console fix it).
"Rescue Terra I" is an original release that has the same bug (you can see it glitching sometimes when starting the rom in Stella 6)
The game also have others small glitches that really annoys me, sorry about that.
I find it a really good game. The concept is interesting, graphics are really nice and it's fun to play. I will definitely revisit it in my next playsession. (and try to find the easter egg!)
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