Validation: 7. Verify tagOn only used on a tag defs (not conjuncts or feature keys) The violation is in the Lib: phIot https://project-haystack.dev/doc/lib-phIoT/curVal i thing the tagOn tag e.g. for curVal, curStatus, curErr should be used with the y:cur def. Please check the Haystack 3 documentation https://project-haystack.org/tag/cur