FWIW
I also run a Lucas but the basic principles should apply to the Peterson. Same original engineers
As far as I know the blades are hammered flat so no tension problems.
With a Lucas the one pass horizontal cut is limited to about 6" because of the saw geometry. The blade should be tilted down slightly. It's in the book.
Wear and tear on the trolley thewheels/bearings can cause the carriage to skew when pulling the saw into the cut as can pulling from different points on the saw trolley. More so when the wheel grooves get excessive wear.
Drive belt slippage can really cause the saw to cut weird.
Adjustments:
There should be a "lead" adjustment for the vertical cut which for Lucas is adjusted to "zero". Saw blade marks on the log, after a thin cut, should show equal marks from the front and back of blade (cross hatching). Same for the horizontal cut.
If the blade is sharpened wrong, slanted top surface on the carbide. it can cause the blade to pull to one side.
Gullet shape on the blade has an effect of sawdust ejection and is a normal wear and tear feature on all circle blades. The inner surface needs to be square to the flat of the blade. Your saw doctor should be on that.
Over heating can cause blade warpage and can cause miss cuts. Is the water flowing enough?