Language Tool Java or Python Wrapper does not validate all grammar check which is getting validated via

if i visit free version
and perform a grammar check “I not feel”
it able to tell me the issue of auxiliary verb and giving correct suggestion “I do not feel”

But when trying the same via java maven repo
or python wrapper language-tool-python · PyPI
it unable to detect the issue and mark it pass

is there any gap between api and ui version?

Yes, the versions are different in the sense that on, some additional rules might be running that are not Open Source.