Text disappears from writable fields

Hi

We are making Pdf documents with writable fields, license rights, and expiry dates. Sometimes the texts that the user write in the fields, disappears when clicking away from the field, and reappears when clicking back. This has happened on mac and pc, but does not happen from any computer (my mac doesnt do it).

Does anybody know what could be the problem or how to solve it? I have a video of this, but I cannot attach it here. I just attached an image. Please let me know if the video could be of any help.

Please, I am not technical at all, so if you can tell me in regular English

Thanks!

Gitte