Test Case keeps saying file not found

Somehow, renaming the folder where the ‘file that became unreadable by Katalon’ is, from lowercase to uppercase, makes the file temporarily readable in Katalon; only on the git branch on which I am renaming it. I save, push and commit, and then create a new git branch and pull that last change to see if it works, and it does NOT rename the folder to uppercase and so keeps failing !!