What you get if you do " show mpls lsp transit statistics " on transit router?
What you get if you do " show mpls lsp ingress statistics " on ingress router?
What you get if you do " show mpls lsp egress statistics " on egress router?
The above commands will let you know the traffic is being lablel switched or packet switched (normal routing). This way you can indentify where is the problem exactly ingress, transit or egress.