I'm playing Space Age with some other mods(Factoriossimo 3 is the most broken with this mod from what i see).
When you copy a build with the long inserters it seems fine, but when you try to put it down the inserter length is getting reset to the length to x handed inserter(whatever one you have turned on).
the placed blueprint doesn't have long handed inserters here as you can see in the image:
https://imgur.com/a/BsFZ6UQ
I've disabled some settings, but it was also broken when they were default.