Hi @CLS720 ,
Do you mean that the IsSearchable property of the ComboBox controls would be changed when you import the app from one Environment to another Environment?
How do you import an app from oone Environment to another Environment? Using "Import/Export package" functionality or Solutions functionality?
Based on the issue that you mentiond, I have made a test on my side (using "Import/Export package" functionality), and don't have the issue that you mentioned.
Please consider import/export canvas app across different Evironments using "Import/Export package" functionality, then check if the issue is solved:

If the issue still exists, please consider turn off the "Improve app rendering (final validation)" option within Advanced settings of App settings of your app, then try it again, check if the issue is fixed.
Best regards,