To immediately address the problem you are experiencing, there are 2 potential remedies:
1. change the Anchor position to 'centre' (for Vertical sub-Page lists) or 'middle' (for horizontal sub-Page lists). This resolves a known issue highlighted by ^SSH ^SHD interaction.
2. setting the 'wrap sub-pages' property to 'YES', resolves a known issue that can occur when quickly alternating direction of certain sub-Page lists. 

These remedies should work as an immediate fix until a new release of TPControl is posted to the AppStore.