why do random files with a letter and number automatically appear in my iCloud

I can try and offer assistance, but if possible could you provide a screenshot of what you are seeing?

The best answer that I could provide is that they are duplicate files. When there are 2 or more files with the same name in a folder or drive together, the one that was created later on will have a number after it, for example [ Image (1).png ]

Again, I can't say for sure what this could be, but this is what I think you are describing.

Hope this helps!

I see, with that in mind I would say the best option for solving this problem would be to contact Apple directly. They would be able to offer a better description of what is happening, and would also possibly be able to solve the problem as well.

Sorry that I was not able to figure out what is going on here, but I hope that Apple is able to find something out.

That it is strange, and not at all what I was thinking of at first. Are they showing up in a specific folder within your iCloud Drive?

Otherwise, it may be from an app that is backing up to iCloud that has a glitch.