Hey Richard Sylvester,
While debugging your issue, I found in the trace that the {with/} and {apply/} directives are already being applied, but specifically to the APEX_CARD template. This is why you're unable to nest another Template Component into it.
As a workaround, you can borrow the HTML from the partial template and apply it directly without using the template component.
Want this feature in Cards region. Unfortunately, the {with/} & {apply/} can't be used in Cards region :-(
Richard Sylvester
Passionate about Oracle Database, Oracle APEX and anything techonlogy.
Yeah. That is what I am doing right now (using the HTML from the partial template). Thanks a lot for checking it out.