Custom structures get cut off at chunk borders when naturally generating in a world

I have a structure that is roughly 35 x 65 x 35. I can load it via Structure Blocks just fine. However, when installing via an Addon, it randomly gets sliced, resulting in an incomplete structure. It appears that this is occuring at chunk intersections. 

I have also successfully loaded this and other large structures on 1.16 as well as 1.14.6 via json files (tens of thousands of them!) And each one is complete.

I hope this can be fixed since the mcstructure files load WAY faster than the old json method