Not just introducing new bugs but reintroducing old bugs which were publicly documented and/or previously exploited. Which you could argue are worse as it’s a lower barrier for detection by attackers, but also on the otherhand by the team/community.

Also of note was that there was already an automated test for one of the high priority bugs that got reintroduced but the that particular tests was turned off.

What confuses me about this is the tests were turned off because they were taking too long. But wouldn't the appropriate behavior there be "run a subset of the tests normally, but run the full test suite occasionally" rather than just disabling the tests completely?

Or turn off some during development but run the whole suite before release?

I have a feeling the a bunch of the tests in that particular category needed to be updated, so it wasn't simply just too long.

Pretty clear that the QA process is at fault here, which is sadly common in the software industry.