If the slide is not sitting on the frame rails, it could cause the appearance of a slant in the front of the frame and expose the spring. I would recommend disassembling the Glock and putting it back together to see if that fixes the issue. Sometimes things can get a little misaligned during cleaning or handling, so a quick reassembly can help get everything back in place. If you're still having issues after that, it might be worth considering
some good slide options as a possible solution. There are a lot of aftermarket slides available that can offer different features or finishes, and replacing the slide can sometimes help resolve issues with fit or function.