No value is retrieved for an item that has the following configuration:

• a template item of type "perf_counter" that uses a macro: perf_counter[\230({$PROCESS_DFSR})\1424]
• the macro is defined on each host that is linked to the template

Server log shows:
Zabbix agent item [perf_counter[\230({$PROCESS_DFSR})\1424]] on host [S******] failed: another network error, wait for 15 seconds

When I use the same item definition directly on a host, everything is ok.
As soon as I move it into a linked template, it stops working.

Another template item with the following key (and host-based macros) works fine, so maybe it's related to perf_counter?:
net.if.in[{$NIC_PRIMARY},bytes]