Why symclone vse terminate takes very long time?

in VMAX 20K, I am facing an issue with the terminate of symclone (VSE). I have used symforce to avoid any hitch, even though it is taking 30-40 minutes to terminate 9 pairs of VPsnap. Data is about 2 TB, but we never seen any modified track recorded at target devices, user is only reading the data from target.

As per normal practice,  "symclone -sid xxx -f filename terminate -symforce -nop" should complete quickly.

Terminate (reverse process) changes the SRC<=> TGT pair state from: CopyOnWrite >>>Created>>>Invalid>>>Delete the pairs.

I have closely checked the query output, and found that the VSE pairs are staying at Created state more than expected time.

Problem is intermittent, daily it takes 11 minutes, but at high time crosses 30-40 minute. Please suggest what to do to rectify this.

Note: No performance deviation noticed in SPA during termination.