It's not an "known issue". It's the design. I have an LS1f and it has
a similar if not identical trim control. It just applies friction, so
it will let go a little when you apply enough forward or aft movement
on the stick. The slipping prevents the spring pressure from fighting
against you for larger fore/aft movements while still keeping the
stick neutral for the small ones. This friction control especially
comes into play each time you transition from thermalling to glide or
vice-versa. It will move when you push or pull harder during those
transitions instead of trying to resist your stick movement. It still
takes a slight adjustment on the trim to neutralize completely after a
transition, but it gets the trim going in the right direction by
slipping and following the stick somewhat. Locking it down would cause
considerable spring tension and will fatigue your arm. I've tried that
and it's way nicer to fly if you adjust it correctly so it moves. It's
an adjustable friction, not a "lock".


Dave