My primary play is an Ironman on OSRS, but I logged into RS3 and I was an Ironman there as well, I was wondering if the Ironman status was linked. Can I play a regular RS3 character and an Ironman OSRS character, or will de-ironing on RS3 de-iron my OSRS account as well?
They are unlinked, and play on one will not effect the other, in any way. You must have made the character an Ironman and just not remember it. For each character I have, HCIM or otherwise, I have had to create the characters every time.