The issue is simple, you are relying on static routing and the HQ router may have reachability information for some subnets while other subnets are missing.
If you can ping from the router on extended ping but not on simple ping, then you need to identify the source IP address of the router and verify the routing table at the HQ router for that route.
Any reason why you aren't using dynamic routing protocol?
HTH,
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Edison.