I have created a template for monitoring DRBD resources (attached to this issue).
Everything works as expected, including item and trigger discovery via LLD.
However, once a host receives discovered items and triggers from the template, I am no longer able to unlink the template from the host.

Steps to reproduce:

1. Create LLD Item prototype (name: LLD Item Name)
2. Create LLD Trigger prototype (name: LLD Trigger Name)
3. Create Item in main template (name: Item Name)
4. Create related Trigger in main template (name: Template Trigger Name)
5. Create depedency from LLD Trigger prototype to Trigger in main template (LLD Trigger Name Depends on: Template Trigger Name)
6. Add template to host
7. Let LLD populate items/triggers.

1. Unlink template from host

Result:

Cannot unlink template "Template Name" from host "example.com" due to dependency of trigger "LLD Trigger Name".

There appears to be no way to unlink or delete the template unless all discovered triggers and trigger prototypes are manually deleted first.
Only after removing every LLD-generated trigger prototype and its discovered instances can I unlink the template or delete it from the host.

This defeats the purpose of having automatic LLD-based monitoring, especially in environments where templates are automatically linked and unlinked via API scripts based on current monitoring needs.