When I ran the Maven test before I synced the postags for ‘rework’ (https://github.com/languagetool-org/languagetool/commit/2c156ce3719150215b73ec06cb35d8ae8bdf1eff), this Maven error message occurred a few times, but it is not repeatable. I put it here for reference:
[INFO] Running org.languagetool.rules.patterns.DemoPatternRuleTest Running XML validation for xx/grammar.xml... Running pattern rule tests for Testlanguage... The Testlanguage rule: PATTERN_REGEXP_MATCH_SUGGESTIONS_INSIDE, token , contains "znel" that is marked as regular expression but probably is not one. The Testlanguage rule: PATTERN_REGEXP_MATCH_SUGGESTIONS_OUTSIDE, token , contains "znel" that is marked as regular expression but probably is not one. 79 rules tested.
As the message says, the tokens do not contain a regexps: