steps

• clone https://github.com/lrytz/sbtproj
• use JDK 11 (OpenJDK 64-Bit Server VM Temurin-11.0.12+7)
• sbt
  • clean
  • compile
  • debug
  • un-commment the println in A.scala
  • compile

A is recompiled, then the log shows

[debug] Invalidated by transitive inheritance dependency: Set(B)

and B is recompiled in a second round.

Doesn't happen on JDK 8.