Standard textbox only takes over paragraphs of first indentation

We're having an issue with text boxes, tested and reproduced with Office 365 (Mac Version 16.22 / Windows Version 1904).

In the slide master we created templates with a styled body (textbox paragraphs: bulletpoint style, font size, different indentation & spacings for 1st and following indentations, see attachments). We also created a text box using the same paragraphs and set it as default text box.

Now the templates work all fine, but as soon the user inserts a new textbox from the menu, it only takes over the paragraphs of the 1st indentation. The defined paragraphs for the 2nd-9th indentation seem to be lost.

How can this be fixed?