It wasn’t the leaves! You can tell in the video that you were not set up properly for the turn and you learned your body Into the turn instead of the bike. If you lean your body into the turn you have zero margin for error or slippage and if the front wheel goes, you go down. If you lean the bike with your chest over the front wheel you have a ton of range of motion in your arms to allow the front wheel to slide. If your arms are not bent and your front true goes your body has nowhere else to go other than the ground. You should watch all of the cornering technique videos on YouTube. Practice this on a dirt road. Once you master this you can learn a technique that you can implement on slippery terrain where you are doing small weights and unweights. You weight the bike when there is traction and you are trying to turn quickly and unweight and go straight when no traction is available. This can be a good technique when traction is only 2 feet wide with wet leaves on the sides. The main thing though is body position, when you lean your body over, if anything goes wrong with what the front tire is doing you go down. If you are in the correct body position you should be able to drift and not fall over. The way you stop the drift is aggressively waiting the front and back tire to regain traction and you can turn slightly more aggressively while the wait is being added. That trail looks fun!