We found that for the Linux VMs that the E1000 gives us the least problems especially regarding the VM Tools. This is unrelated to the SureBackup issues I have though.
In fact with the VMXNET3 adapter it introduces a similar problem in Windows where a new adapter is used during SureBackup and an IP is not allocated. There is supposedly a hot fix from Microsoft to resolve that. https://www.veeam.com/kb1570