[cs-szazz]

11,503 files, 1,431,195 lines of code. (spread out over <50 Gradle modules).

I think the main problem is that Gradle doesn't have the same support as Java for ABI compatible changes, so invalidation of modules are more common.

[stepbeek]

This article points to ABI as an open optimization problem in kotlin:

https://blog.jetbrains.com/kotlin/2020/09/the-dark-secrets-o...

I think you're right - ABI compatible changes are likely the culprit.