I notice there's a new 1.6.10 Kotlin Plugin build, 213-1.6.10-release-923-IJ5744.223 -> 213-1.6.10-release-944-IJ6461.79. What changed? The linked change log is just for 1.6.10 in general.

See https://twitter.com/kotlin/status/1483142332367134722

Unfortunately, the 923 version was working well for me with 2021.3.1, whereas 944 is throwing a steady stream of internal errors. I'm reporting them all via the built-in error reporter.