I've checked the issue and opened a bug upstream to pyparsing [1] as this is indeed a regression. Running CI on cumin I've also found that pylint is reporting new issues related to pyparsing code, for which I've opened a separate bug upstream [2].
[1] https://github.com/pyparsing/pyparsing/issues/502 [2] https://github.com/pyparsing/pyparsing/issues/501
