I have created a new Initiative issue type as described here and it look good, even if i wonder what the number in the first column means:

It seems to apply properly in Advanced Roadmap view:

But then I am checking the newly created Issue Typ via REST:

And the hierarchyLevel for the Initiative type is zero even If I expect it to be 2 (one higher than Epic). As A result I cannot create an Epic with an Initiative Ticket as a parent. This is a bit confusing.
Any Ideas ??
Thanks,
Florian