Thanks for reply, isolation is what i’ve discovered when i started to research the topic.
I’ve found a workaround for this problem.
I included the child portlet into parent portlet, thus making child portlet render DIV tag insead of nested FORM. That way every field is submitted into parent portlet request (what is strange is the fact that child portlet is executed normally but with empty request values map, is this the way it should be?). I then manually map submited child portlet fields to business data as the fields have easy to decipher HTML IDs.
To pass the data the other way i use session and it does the trick.
For now its sufficient solution.
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