I have made small signs in 3/4 inch oak with peoples names on it for years. (One name per sign.) I am doing my annual batch and am on the last one. For some reason, the name is not carving nearly as deep as usual. I restarted the project and carved again and it is doing the same thing. I have confirmed that it is the same text as always, I am using the right bit (90 degree) but it suddenly is much less deep.

It doesn't look bad, but is definitely different from the other signs. Anyone have any idea what's going on?