Basically, I leapt from the shoreline into the open top of the log, and I cannot climb out of the log. The game automatically Saved right when I got stuck too. :(

Try and spam climb (hit space bar near a ledge, the inside of the log counts as one) until you get out. Might need a few attempts

There's a mechanic that's not mentioned in the tutorial or anywhere else as far as I'm aware, but if you crouch and spam climb (double tap space while reticle is red) you can consistently climb up slopes like the one in the log. (This isn't chance based, it works 100% of the time)

settings>binds>debug tp (usually it's " . " on your numpad)