Oracle Forms

I'm getting the following error when trying to commit a form in Forms 6i
FRM-40403: A calling form has unapplied changes. Save not allowed

The scenario is the following:

I have Form A which calls Form B, when I save Form B I get the error and nothing is saved on that form... The problem is that I have another form, lets called it Form C which also calls Form B and I am able to save Form B there... the call I'm doing its exactly the same in both forms A & C,
CALL_FORM('FORM_B', NO_HIDE, DO_REPLACE, NO_QUERY_ONLY, pl_id);

I googled the error but the only workaround I found is using OPEN_FORM to use another session, it actually works but then I loose some global variables I set in Form B so I can use in Form A; and the actual course of the code after doing the call_form doesn't execute.

Any ideas what could it be??

Thanks in advance