A router that does not have TE links within a given IGP area or level will not have its router ID discovered in the TE database by other routers in this area or level. In other words, an auto-created LSP mesh cannot be signaled to a router that does not participate in the area or level of the ingress LER.
A mesh LSP can be signaled using TE links that belong to the same IGP area even if the router ID of the ingress and egress routers are interfaces reachable in a different area. In this case, the LSP is considered to be an intra-area LSP.
If multiple instances of IS-IS are configured on a router, each with its own router ID, the TE database on other routers will be able to discover TE links advertised by each instance. In this case, an instance of an LSP can be signaled to each router ID with a CSPF path computed using TE links within each instance.
If multiple instances of IS-IS are configured on a destination router, each with the same router ID, a single instance of LSP will be signaled from other routers. If the user shuts down one IGP instance, this will have no impact as long as the other IGP instances remain up. The LSP will remain up and will forward traffic using the same TE links. The same behavior exists with a provisioned LSP.