We have a 2011 FR Grey Wolf 26RL. Three years ago our slide, which had gone out just fine, would only retract a very short ways as one side moved normally and the other side moved just a little which caused it to go catawampus and stop. We had a mobile tech come take a look and he figured out that the motor on the barely moving side was jammed crookedly in the mount. He simply loosened it up, realigned it, re-tightened the bolts and the slide worked fine. He did check the control board and wiring and they were fine. Perhaps the motor on your slide was jammed and your pushing on the slide straightened it out.
By the way, when the slide first would not retract another camper suggested that I push the "in" switch until the slide stopped, then push the "out" switch a quick very short burst and then push the in switch again. I did this and was able to gradually jockey the slide all the way in. Took quite a few back and forth hits to move it all the way since it would jam each time after just a few inches of retracting.