Steps to reproduce:

1. Import the host test-usermacro-lld.yaml
   Note: it contains a host with host macro, LLD with 1 item prototype, which contains macro with macrofunction ({{$TEST}.regrepl(3,4)}), one regular item with same configuration as prototype.
2. Start the server
3. Execute the LLD rule on imported host
4. See the result

Result:
Item is not discovered, message is displayed:

Cannot create item "zabbix[stats,127.0.0.1,10051]": Invalid update interval "{{$TEST}.regrepl(3,4)}".

Expected:
User macro with macro function is a valid configuration for item, so item should be successfully discovered.  On the same host, can see, that regular item is working as expected, with a same value of Update interval.