Based on the information reported by another user to the support team overnight, and taking into account the information shown at the screenshot, it is a bug in the software which is caused by a misinterpretation of the “###.” at the beginning of the question as an element of a numbered list.
As a side effect different devices may remove the number all together, remove it from a question in the disabled form (appearing behind the curtain) or replace it with a bullet point.
This was not intended. The developers are aware of it, but at the moment there is no timeline for when this is going to be fixed, as this is still a new issue.
As a workaround, I can only suggest changing the question text to start with e.g. “[6.] question text…” or otherwise affect the beginning of the question so that it doesn’t start with "###. " or "###) ".