Hi Andrey, I don't consider this issue worth to be fixed, since it's a very unusual usage, and it's not possible to predict which kind of content will have a field in configuration time.
Please, let me close the issue, since you have actually resolved your problem.
Sure thing, I did not expect you create a run-time parser, Fidel. I think a warning message would be enough in case the input string doesn't follow JQL rules. Also, there are might be custom search functions and you can't check them all, I guess.
could you please remind me how to disable syntax checking of JQL requests? I can't find this info the documentation.