Kotlin: Unwanted "Java HotSpot" warning line in output making the test fail

Hello Team,

when trying to test a solution for the 16x16 Sudoku community problem with Kotlin, the test fails and the output starts with:

Java HotSpot™ 64-Bit Server VM warning: Options -Xverify:none and -noverify were deprecated in JDK 13 and will likely be removed in a future release.
… followed by 16 the lines of my (hopefully) correct solution.

The exact failing message is because of the unexpected 17th line (the last line I sent, which should have been the 16th, but of course the warning shifted them)

Kotlin works well on at least another problem, which I have solved successfully.

Is there anything I can do to avoid that ? Some language feature I’m using which triggers that warning ?

thanks in advance for the investigation,