It is a problem because it keeps me from autosaving files from CAD, which I could do before.
If you are referring to what is shown below, you're barking up the wrong tree. Your auto-save issue is caused by something else entirely. Read below for the explanation.
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If you look at other folders, you will see that they all have that same "indicator". It's perfectly normal and essentially meaningless and has always been that way. It will not cause any problem.
To be clear, that "indicator" does not mean what you think it means. The folder itself is not read-only. You can verify that at a command line with the attrib command.
It's actually an operational item rather than an indicator. It always shows the solid box indicating that one or more files in the folder may be set read only. So, it really isn't any kind of indicator at all. But if you check the box, it is a command to tell Explorer to make all files in the folder read-only (it will ask for confirmation). It can also be unchecked to make all files in the folder not read-only.
It's an example of incredibly bad interface design.