Veeam MP alerts about unreasonably high values for highest latency on VMs (see screenshot below):
The same latency values can be observed in VI Client performance charts under disk/real-time during snapshot deletion. The values may also be negative.
This is a known behavior of VMware. KB 2001676 by VMware describes the behavior in more detail.
False alerting on Veeam side has been eliminated in the updated Veeam Virtualization Extensions VMware Monitoring pack. Please, download here. After installing the fix the version of the Veeam Virtualization Extensions VMware Monitoring MP will be 126.96.36.1991.