There is a known issue in 20.x, owing to bug-id 59645, wherein multiple sync-from tasks are generated in the director corresponding to a sdwan-branch-info-update notification sent by the controller during a wan link flap events on the Branch(es). This slows down all the tasks on the Director in general and can impact tasks like staging/onboarding, template commit. director commits etc depending on the volume of "sync from" tasks being triggered. 

This bug is fixed in 20.2.3 release post Oct 12 2020 - below link has a recent 20.2.3 director image

https://versanetworks.box.com/s/7h7qltdte7j0xdkogxw5ukqvzyghf08j

For ex, consider the below wan link flap events on the branch

Branch logs:

This would result in "sdwan-branch-info-update" events, which are propagated by the controller towards the Director

On Director, we end up generating a "synch from" task corresponding to each of the above events

Director vnms-spring-boot.log

If there are just a few branches that are causing the sdwan-branch-info-update events, owing to unstable wan links, one can look to shutdown the problematic wan links to reduce these events. However, the proper solution here would be to upgrade because one cannot always control the network behavior (wan link flaps)