Steps to reproduce:

1. Use template with LLD which will have item prototype, item prototype filter, prototype trigger
2. When items and triggers will be populated change in template definition of the item generated by LLD by for example change name, change definition of the filter or change definition of the trigger

Result:
After next cycle of the LLD update updated definition of the items, items filters or triggers will be not applied/populated.

Expected:
After change LLD prototypes on next update of the LLD items, filters and triggers should be updated. I've not tested this with graphs prototypes but I suppose that effect will be the same.