Thanks for the replies.
The problems I've been having lately all happen during resawing, and drift has become a serious issue. After doing an upgrade a couple of years ago (silicone rubber tires, new fence and a bunch of new blades), everything had been running smoothly. I would just set up the fence and cut away. Now the blades seem to have a mind of their own.
From observing what's going on, all I can see that's a problem is
the knurled nuts on the side guides tend to loosen, no matter how much I hand-tighten them. On a couple of occasions, the guides closed and clamped down on the blade. This is all fairly recent. I haven't yet resorted to using hand tools to tighten them and I don't believe I should. That's not how they were designed and I've never needed to in the past. The times the guides closed on the blade may have scored the insides of the guides. I can't see any gouges but at certain angles I do see what might be slight scoring. When I looked at this picture through the camera, I thought I could see scoring, but the picture didn't show it.
This morning, I took a piece I had earlier tried to resaw, but drifted badly, and cut it freehand from the other end. I zig-zagged the cut until I met the previous cut. When I opened the two halves, I saw the previous cut had burn marks. The part I cut this morning didn't. The blade I used previously was fairly new. When I was making the previous cut, I attributed the burning to the fact the drift was pressing the wood against the fence. Maybe the blade had prematurely dulled? I know the teeth were clear of the guides, so that shouldn't be the problem.
Whatever it is, I think it's somewhere between the side guides and the blades. I didn't consider the blades being the problem because they were fairly new. But maybe Lenox dulls just as quickly as Woodslicer? I've never been crazy about the friction created with the OEM setup. Roller guides should get rid of that. I realize they aren't cheap but if they work, I won't be ruining pricey woods and my frustration would end. There's value in that.