Just for the records: As far as I can tell, the bug that caused the above failures was an "off by one" in the multi cache implementation. It was fixed with https://github.com/perl6/nqp/commit/7eaebf5abd
[perl #128123] [JVM] in some cases wrong multi candidates are selected
Christian Bartolomaeus via RT Wed, 13 Dec 2017 12:36:12 -0800