this is typical of the gears 'jumping' the rails - and unfortunately there is no ready easy fix for that, since the whole slide room would need to be removed in order to reset the front and back gears.
This happened to ours, though we could still continue using the coach and driving it with this slight extension...but we were able to continue extending and retracting it for several months until we could get into the Thor service center in Wakarusa, who replaced the rear slide mechanism/wall column. No problems since, in another 50,000 miles.
'14 Thor Palazzo 33.3 compact diesel
KingTailgater2 Dish, 100w/5amps roof SOLAR, BlueOx, 100,000+mi since '14... US, Alaska, and Canada... from GA, then NC, now N AL : )