ATP Alerts Tor Exit Nodes

Hi All,

I wonder if anyone can help me clarify the following, we start receiving standard ATP alerts for the past month as per bellow, usually im able to investigate this alerts and they either are DNS recursive queries performed by out forwarders on Spam domain emails  received and rejected by the SMTP proxy, or Web sessions hijack attempts trying to redirect traffic to malicious domains, but recently i been baffled by a a recurrent alert as bellow where im not able to make much sense, i parsed the logs for our SMTP proxy that shows traffic to a Tor node from what i can only assume being SMTP connections rejected by the UTM  does anyone have any idea on this ?

A threat has been detected in your network The source IP/host listed below was found to communicate with a potentially malicious site outside your company.

Advanced Threat ProtectionDetails
Total Events: 2
User/Host Threat Name Destination Events Origin
1 192.168.7.250 C2/Generic-A 185.220.100.254 
2 192.168.7.250 C2/Generic-A 185.220.100.254