Can't see data when entered into data entry fields

Weird - was working, now when I run in simulator (and on build on iPhone), the windows show up with data entry fields, I can enter data with satisfying clicks, but cannot see the data. Also, when I move to try to calculate something that should be ninth data fields, I get an err]or which implies that nothing has been saves. I am running Catalina, which says the I can’t run 32 bit apps, but it still compiles and displays.
Is there anyone else with similar problem?
Any ideas?

I created a Feedback case for an issue where I discovered that apps run on iOS 12 or earlier had this problem. The workaround for now is to assign a ColorGroup to each TextField.

Thank you Art!
Works a treat. If the user runs iOS 13 - is the problem fixed?

I didn’t notice a problem in the simulator with iOS 13, but better to be safe.

Just put it on my iPhone and it is working. I really appreciate your help. I put it on an iPhone with iOS 12.4 yesterday and had a problem. I will get the person who owns that phone to upgrade to iOS 13, and let you know if that fixes the problem.
I will update the app and reinstall later next week.
Thanks again.