Updating DAX Expression Causes Errors!! HELP

vanessafvgnothing in my data has changed. i did check to see if there was any duplication and there hasn't been. i should have been more clear, when i said it is affecting all of my models i meant all of my power bi data sets, which are separate from one another. i have another sample data set i have new screenshots from as the problem continues to persist. as you can see from the screenshots below, i can create a calculated column in the calcualted table but when when i click into a different column and click back in, it replaces the calculated column with the table.