International mastering understanding

I'm trying to gain a better grasp on mastering. From what I gather - prior to a certain year/time period, there would be multiple masters done for different regional releases. For example - I've noticed that The Cure's 1985 "The Head On The Door" was mastered by Arun Chakraverty at The Master Room for the UK/EU release, while Dennis King at Atlantic Studios handled the US master.

My questions:
1. Was this common practice for different world regions? If so, was there a point where the same master was used worldwide for the same release? It seems crazy to me to have different mastering engineers for the same release (not counting reissues/remasters). I assume at some point this ceased, and the same master began to be used worldwide.

2. For major label releases such as the Cure release I referenced above, is this pretty standard - i.e. Elektra in the US would have its own go-to mastering studio, while Polydor in the EU would have its own?

Apologies for any rudimentary understanding or verbiage - that's why I'm turning to you guys! Thanks in advance for any help.