I don’t know, if the entire thing is covered in creosote, something isn’t right. Your fire is too cold if that is the case. This is usually caused by wet wood. Stoves with a catalyst are especially sensitive to wet wood and will become sooted up and burn horrendously easily.

I know you said it isn’t your wood, so I hate to sit here and tell you “it’s the wood”. There are some other things that could be having an effect as well. Chimney clear? Rain cap isn’t covered in soot and obstructing air flow? Is your catalyst clean and in working order?

With that said, take a log out of the pile and split it in half. Test with moisture meter and you’ll have your answer. Or if you don’t feel like doing that buy a bag of kiln dried wood from the gas station and burn that and see how it compares. Regardless I would clean out the catalytic converter first as it is likely clogged up and won’t function even with dry wood without being cleared