I have been using an action to capitalize license plate entries, as advised by Aleksi. All entries need to be capitals in order to count the duplicate entries, which is the most critical aspect of the app. The AppSheet group aggregate COUNT does not aggregate same license plates if some are lower case and others are upper case.
This always works in my Publisher PRO plan apps. But it often creates duplicate entries in my Premium plan app. The duplicates are most often not consecutive in the database. No workflow is being used. Are actions that “set values of some columns in a row” functioning in Premium plans? There are no warnings shown in the config interface to this effect.