Form fields/Buttons displayed wrong or missing | Version 21.2.0.17204

Hello everyone,

since we updated our tablets to Version 21.2.0.17204, we encountered two problems.

Checkboxes which are hit by our users won't visually update, although they change their state in the background. (We tried to forward the file after checking some boxes and saw they actually changed their state.)
Furthermore a button, which is used to open a new mail to some specific e-mail address, isn't displayed anymore.
Further investigation showed the button apperently is there, but not visible as usual.

The document hasn't changed at all and is working properly in different versions or products.
I'd be really grateful for some advice, information oder pointing in the right direction, since the pdf I'm talking about is pretty important for some workflow in my company.
Our technicians rely on it during field service.

The PDF was generated using the recent version of InDesign CC.
In the attached sample I only removed our Logo and changed the mail address.

Best Regards
Chris