Slight bug but something you could fix next update. Had to go back to slime lake for the post card I missed after everything that goes on. Went to go back the way I came, to the campsite, but it wouldn't let me. Instead gave me the message about find El'lena. I had to traverse the whole forest path instead. Thankfully a short trip.
It was the transitional path to the slime lake camp and it was after the Kadone fight and the whole mind guardians in El'lena's head. Left Kadone's hut and headed to slime lake campsite and down to lake slime. This is just before you have to head north to the bridge full guards who say "no entry". (Funny lil place too)
Hope this helps make it more clear.