Steps to reproduce:
1) Create Host with item and trigger (trigger1).
2) Create template with discovery rule, item prototype and trigger prototype.
3) In trigger prototype add Host trigger dependency (of trigger that created before).

4) Export template.
5) Delete created template.
6) Try to import template back.

Result:
Error message

Expected:
No errors. Template imported.

P.S.: added exported host and template file.