Some 4-place models have reported movement in the pitch trim tab linkages at the front bushing.
The original kit-sets had a rod-end bearing at the aft end of the push-rod, but a plain bushing at the front end. The plans now show a rod end bearing at both ends. Patrol kits have rod end bearings on both ends as standard, and future 4-place kits are planned to have them as standard also.
Replacing the front bush with a rod-end bearing appears to be a good long term solution and is a relatively simple fix.