the mod is not compatible with 9944 it has varying issues running on all builds above 9921. but 9944 in particular converted the game engine from gms1 to gms2 and broke quite a few things with mods.
that error can happens sometimes entering any custom area (its not actually scrapyard) not just this mod. it is on the list of things to fix for NTT 9945 but yal has been working on other projects. im not sure why the bird is locking on the gms2 builds but i think golden epsilon has an edited version of the mod floating around that can run on 9944. though you would still get the chest errors
Any idea when NTT 9945 will be released ?
As for the birdboss infinite flying softlock, i found a workaround by editing the boss' script and removing its ability to fly altogether. The problem is that the mod is also broken on other areas, such as custom boss intros freezing the game (and needs to be disabled) or the crystal caves level not loading at all, preventing for playing past big dog bossfight.
there has not been any news of ntt 9945 since around 9944. yal (yellowafterlife) seems to work on it for a week or 2 every few months (probably between paid jobs). he seems more invested in getting a stable gms2 version of the base game (with 60fps) than pushing a new stable ntt build. but that requires contacting rami to push steam updates which isnt the easiest thing to my understanding. but i dont really know anything. he posts in and checks the 2021_beta_bugreports channel in the nt discord. you can ask there or tweet him i guess.