I have ze good news and ze bad news!
Good news: Having sharpened the offending barrel trimmer again, I realised that I was not sharpening it enough. I used it yesterday on some Pau Rosa blanks and some Lignum Vitae blanks without any burning.
Bad news: Following the warning in an earlier post about the risk of tearing Thuya Burr, even with a sharpened barrel trimmer, I decided to square off the ends using my Pro Edge. Not a good idea! While it squared off the ends nicely, it has clogged the belt badly. Any advice on cleaning the belt or will I need to bite the bullet and buy another one?