Made friends with my SuperMax 16-32 today.
Bought this thing last year and played with it a bit. Into a furniture project now with quite a few QSWO panels I wanted to finish sand with the drum sander. Started running a couple of the shorter panels through this morning and was getting snipe and some waves in the panels. Was thinking about getting rid of the sander as I was working these panels.
So, why are those ridges showing up at the same distance from the ends – took me a while to realize my infeed table was set too high. Played with it a bunch. Ended up setting the infeed and outfeed tables low (straightedge on the sander table, push down on the feed belt and make sure there is daylight between both ends of the infeed and outfeed tables). Infeed and outfeed tables are helpful but this isn’t a planer and the upper rollers don’t have enough juice to overcome the differential between the feed tables and the sanding table.
Pushing down on the work during the feed and on the exit of the work does make a difference, and eliminated snipe, as others have mentioned on posts I researched.

Hope this helps someone that it is experiencing similar issues.