Some quick tips from our experiences on this if your still having issue
There is known issues in at least 20.6 with this happening when you have encryption enabled (which everyone should) in your jobs. Needs an update to BE 21.2 for the fix. There was a new set of vmware api's implemented that solve a number of things in the more recent releases of vmware. Sure sign this is the thing for you is to look for crashes in some of the backup exec services. In my experience, if you get a crash in any of the critical services you need to do a server restart.
Also, make sure your vmware hardware and tools are current for the version you are running, and keep your vmware stack current with it's patching.
I also found that, using things like write limits on your target storage isn't always enough to limit load on the server, and at times, load and internal latency. make sure your OS drive and database is on fast, ideally flash, storage, and your not running to many jobs at once. stagger out your job start times, and don't have to many servers in a single job. pain in the arse if you need to take a full out of sequence.