Hi Rabi, this is the issue with VMware Tools quiescence. VMware Tools quiescence is not used by default when you create snapshot with vSphere Client, which is why you are not seeing the issue there. Try to disable it in the advanced job settings, and you will see that the issue will go away.
Although for DC you definitely want to enable Veeam VSS (doing this will also disable VMware Tools quiescence automatically). If you have multi-DC environment, then generally speaking backup or replica performed without leveraging VSS is worse than not having backup or replica at all