Hi, of course!
I uploaded (temporally) the complete metabox form here:
https://github.com/Flewps/metaboxproblem/blob/master/dano-cerebral.php
(This is one of many 'metabox' that I load in this project. This is the reason that because it's return an array and isn't into a wordpress 'rwmb_meta_boxes' hook (I do this after load all)).
In this case, the problem isn't the heading field (I think), it's a group with more of three fields. It's posible that the problem is when Metabox Columns, and their column counter, decide that field is the last of the row and close the column and the row before the time. And this happens in heading, divider and groups fields, far as I know.
Thank you!
