"Multiple instances" refers to having more than one occurrence or example of something. It means that there are multiple versions or copies of the same thing, which can exist simultaneously or at different times. Full definition
And all of these sort of multiple instances of you are operating simultaneously and in parallel. (edutopia.org)
Spot almost causes more damage than he's worth in multiple instances but the heart of the character has aspirations of love. (nerdlocker.com)
But another major factor is that games have become so much more detailed in the last few years and consoles can't run multiple instances of the game at the same time anymore. (thisgengaming.com)