Steps to reproduce:

1. Create template with some trigger having function expression containing backslashes, like:

   find(/host/sip.remote[5060],#3,"regexp","^OK\s+")<>0
   

2. Make this template applied to hosts from autoregistration action (link template when host registers in Zabbix)
3. Register new host susceptible to autoregistration applying this template

Result:
Host trigger expression will be correctly inherited from the template, but backslashes will be escaped, resulting in wrong expression like

find(/host/sip.remote[5060],#3,"regexp","^OK\\s+")<>0

Expected:
No such escaping, expressions should be copied as is from templates.