I experienced the same problem
Mech triggered, lighted arrow kicks on, light turns on inside mech hole, mech starts to lift but wont come out of the hole, sometimes it moves up and down a quarter of an inch repeatedly as if its trying to pop the rest of the way up but and can’t then tries again. Mech scores a hit, never coming out of the hole.

I got help from JJP customer support. The basic fix was find any places where the mech could be rubbing on the play field, lift the mech up and push it firmly in the opposite direction allowing that the wood gives just enough for the mech to move into a better position. It should be pointed out that you should use gloves as the flap on the mech will cut your hands if you're not very careful.

The height adjustment for the mech worked for my warg that was having trouble popping up as well, I just raised up the black bumper pad that acts as the stop for the mech just a small amount and everything started working perfectly. Apparently the weight of mech slamming down will take this out of adjustment over time. Supper easy fix once you know what to do.

Cheers! and Thanks!!
So I had my book screen stop working as well, my Elite Pinball topper still displayed all the information correctly so having to hunt down the problem was easy, just by swapping VGA plugs from the topper to the book screen. Clearly the book was the problem. I found your shared link for purchasing a replacement screen and in less than 5 days I am proud to say, I'm 100% up and running. Price was cheap and the actual swap out was just a short exercise in patience. Thanks for doing the leg work. I can recommend https://www.buydisplay.com/lcd-4-3-inch-tft-display-module-in-480x272-vga-video-av-driver-board perfect solution.

I bought these from Tilt Graphics: https://www.tiltgraphicsinc.com/product-page/hobbit-treasure-trove-gameblades. They look great in the game especial if you get the 3d printed coin flipper mods. However the game is so tight in the cabinet, it will ruin the blades so you HAVE TO buy https://www.pinballlife.com/interior-cabinet-protector-blade-set.html and use them EVERYTIME you lift the playfield. No exceptions. Look at the image of my game with them installed.

Hobbit (resized).jpg

Black Arrow Also has a special splash screen, showing the firing of the windlance. Mine also has a more gold headed Smaug as well, you can see the attached image.

IMG_2165 (resized).jpg