Describe the bug
When minecraft loads a structure template from nbt, it checks the DataVersion tag to see if it needs to be updated to the current version of minecraft, and if so it runs it through the data fixer upper to update it.

By providing outdated structure nbt files in your "mod", you force DFU to process any structure loaded from your mod, causing increased memory and cpu utilization.

CTOV Version

3.4.2

Add-ons used (Before 1.20)

Do you install Lithostitched?(1.20+)
Yes

Ideally, if you are building a fake mod anyway, it may be best to run the structures from a folder through DFU and write them back out to nbt during datagen so that any version you release matches the nbt you provide