It could be the burrs going blunt. Since the burrs in my Sage grinder contacted (after I followed that stupid advice to adjust the burrs closer) it's kicked out a lot of fines. It's a result of losing the sharp edges at the very fine end of the burr where it's most critical for a consistent grind. I really must replace them.
I’d definitely give it a good clean if you’ve put that much coffee through. At least it would rule it out if nothing else.
I had a quick google though and other people seem to be saying the same as you about fines getting worse.
It could be the burrs going blunt. Since the burrs in my Sage grinder contacted (after I followed that stupid advice to adjust the burrs closer) it's kicked out a lot of fines. It's a result of losing the sharp edges at the very fine end of the burr where it's most critical for a consistent grind. I really must replace them.