Steps to reproduce:

I was able to reproduce this issue on Master branch, go version 1.23 (although issue appears with earlier versions of Go), MongoDB version 4.4.6

1. Create MongoDB instance (I used the guide here https://confluence.zabbix.lan/display/QA/MongoDB+-+quickstart)
2. Build Agent2 MongoDB plugin and configure mongodb.conf file to point to the plugin executable
3. Create a host on the frontend, add Agent interface and assign template MongoDB cluster by Zabbix agent 2 and navigate to latest data

Result:
Item configserver heartbeat returns following preprocessing error:

Preprocessing failed for: {"asserts":{"msg":0,"regular":0,"rollovers":0,"user":56,"warning":0},"connections":{"active":2,"a...
1. Failed: TypeError: cannot read property 'clusterTime' of undefined
at [anon] (duktape.c:60534) internal
at [anon] (function:2) preventsyield 

Item last seen configserver returns following preprocessing error:

Preprocessing failed for: {"asserts":{"msg":0,"regular":0,"rollovers":0,"user":56,"warning":0},"connections":{"active":2,"a...
1. Failed: cannot extract value from json by path "$.sharding.lastSeenConfigServerOpTime.ts.T": no data matches the specified path 

Expected:
Items do not return preprocessing errors