Markdown - Transclusion

If i try the following {{Jn,1}} or {{Jn:1}} it works BUT if I try {{Jn.1}} it does not work !
Any reason for that?
Ty for your help

Works actually in all cases over here.

finally it woks in this format {{Jn 1.1.md}} but not with {{Jn 1.1}} weird …