FRR pimd - PIM prune is not forwarded toward source from middle hop router

[NilBhosale]

I am using FRR pimd for PIM protocol. I have below set UP

1. Multicast receiver (R)
2. Rendezvous point (RP)
3. Middle HOP Router Router (A)
4. First HOP Router Router (B)
5. Multicast source (S)

I have multicast communication working from source (S) to receiver (R) for Group (G). So I have (S,G) tree created from RP to source(S).

Issue:

1. Sent IGMP leave from Multicast receiver (R) ,it is received on RP.
2. RP sent PIM Prune message toward the source to Middle HOP Route (A) on eth0 and eth0 on Middle HOP Route (A) is pruned.
3. PIM prune is not getting forwarded on eth1 on Middle HOP Router (A) and this interface is not getting pruned, after approximate ~3 Minutes 10 seconds prune message is sent from eth1 on Middle HOP Router (A) and eth1 on Middle HOP Router Router (A) is getting pruned.

Find below flow diagram for the set up and issue.

Could anyone help me please for why PIM Prune message is not getting forwarded toward source immediately from middle hop router(A)? Am I missing something or is it expected behavior ?