Problem could be something as simple as your starting grip.
If you're right handed, you probably start a right to left roll
with your right hand palm up- thumb up at the end of the roll.

Rolling right to left,if you start the roll with your palm down
your wrist is bent in an akward position but lets you finish
the roll thumb up. If you start a left to right with your thumb
up, and finish the cut plam up, as you roll the skew there can
be a tendency to push the cutting edge back "uphill" - even
just a ittle and you can get a spiral cut started.

Examine your right hand grip as you roll right to left and
left to right. See if your thumb is up at the end of both
rolls.

Are you cutting long point down or up? I get more spiral
cuts long point up than long point down - but that could
just be me.

Is the end of the handle higher or lower at the end of the
roll than at the start? For me, if the handle ends up lower
I get more spiral cuts.

Probably that's all clear as mud.

charlie b

ps: putting a slight curve to the cutting edge made using
the skew a lot easier - for me.