In a specific case where permits clause is present, and some classes are load from source and some from classfiles, a false cyclic inheritance error may be reported:
---
$ bash bug.sh
preparing test:
actual test (should pass, bug fails):
src/T.java:1: error: cyclic inheritance involving T2
sealed interface T permits X, T2 {}
                              ^
1 error
---

Please see the attached script to reproduce the bug.