So, I hope you realise it is common, accepted and standard practice for the last 20 years for a project with midi information for the track to actually start at measure 2...
ALL midi gear (including the virus) takes time to sync to a host and frequently there is significant control & setup information being sent from a sequencer to the synth... patch changes, part volume & pan levels, RPN, NRPN and modulation information. having this information being dumped at the same time as note information can cause problems.
To close, there are
no issues with latency or midi event timing with the Virus Ti & Sonar if you ensure the first Virus clip starts at measure 1, with song start at measure 2.