In servers, attributes don't appear to display correctly. Clientside it is perfectly normal- all modifiers display fine and are colored correctly, etc., but on the server I have set up it does not display anything. The NBT tags are there, though- and using /data get, I can even read which modifier is supposed to be displayed. For some reason, the item just does not display the name and attributes; e.g "Dented Iron Chestplate" displays as "Iron Chestplate" with 2 NBT tags. Interestingly, there is a commented out section in the Tiered.java file which calls a method on the client which would apparently write the item's modifier- is this correct, or is there a reason why it's commented out?
Thanks for the help.

Fortunately, opening a world in survival and messing with items appears to fix the issue. Still would likely be a good idea to figure out why it happens in the first place, but at least there's a workaround?