By BESR you are referring to Symantec System Recovery, correct?
Since Veeam is an image level backup at the hypervisor level you should be good. I have a few legacy servers backed up with Veeam that still have System Recovery installed/running and have not seen an issue with Veeam. Of course, I have not had to recover anything with Symantec in my time here (and I am not sure anyone who worked here previously has had to either to be honest).
Your amount of change blocks might be a little higher if System Recovery is flagging files but I would imagine you won't see a huge difference.
Veeam Certified Architect