Inlinetasks are always interpreted to be of type heading. This causes
multiple issues e.g with export.

I think that I could track it to the function org-element--current-element,
where the check for headings is before the one for inlinetasks, while
inlinetask is just a sub-type of heading.

Hence the (custom-) formatting of inlinetasks at export does not work.

Org mode version 9.5 (9.5-gced2b3