Type Definition not visible if not used, and not deployed?

Hi, I added a custom type “Datum” to my doc model, because I need it for a calculation in the Print Engine. But I don’t need any field of this type, I just need the custom type to be available in the Print Editor (to assign a data type to the result of the calculation).
In the SME, the custom type doesn’t appear into the list, although it is in the Json (I added it manually, copied from a test model). In my test model, it is necessary to create a field using the type, else it is not saved properly.
Is it a feature or a bug?

How can I make the Type Definition available to the Print Editor, without creating a dummy field in the doc model?

Currently I’m using SME 7.1.2 - I can’t migrate yet (but soon)

With A12 2022.06-ext2 (SME 8.1.3) and 2022.02-ext3 (SME 7.1.5), I could not reproduce the issue.
But when I used 2022.02 (SME 7.0.0), the code for TypeDefinitions was missing the fieldType information. After adding it manually, the model is considered invalid by the SME.

Meanwhile we could migrate to A12-2022.06, and Print Team also made a bug fix in Print editor, so my problem is solved.