Hi @alietzau ,
Could you please share a bit more about your issue?
Do you mean that the Choice Dropdown box could not work when your app is in Player mode?
Based on the issue that you mentioned, I have made a test on my side, and don't have the issue that you mentioned. If you create a custom form in your SP list using PowerApps, please consider remove the custom form from your SP list, then re-create a new one for it, check if the issue is solved.
If you create a standalone canvas app based on your SP List, pease make sure the Items property of the ComboBox control you are having issues within your Edit form is set to to following formula:
Choices('YourSPList'.ChoiceColumn)
If the issue still exists, please consider re-generate a new app based on your SP list, check if the issue is fixed.
Best regards,