It should be reversing. I see no reason why it should get stuck up there. It certainly won’t clean a narrow ledge line that effectively but, once it gets up there and runs for a minute or so, it should reverse.
Can you watch it while it’s on the ledge? As @Arizonarob said, the S300i can do floor only mode.
So take it out of the pool... and store it out of the sun. Right, gotcha!A practical take away from this is the following - removing the robot from the pool when not in use will likely improve the longevity of the cord. I do typically take my robot out and, unlike a lot of robot owners, I have almost no issues with cord tangle or cord splitting open.
Thanks for the great write up..
Something I'll be doing in a year or so..