Hello Bud,
I can see what you're saying.. I would be interested to know how the networks behind the 1841 get redistributed back into the MPLS core.. I am taking a guess here but I assume your network maybe setup something like the below where you have these switches reside on potentially three different networks?
If this is the case I would be inclined to see if you lost any Layer3 protocols that may be used for redistribution back into the MPLS core.. this could be isolated to the router on site.. are there any logs on the device to support whether that device lost visibility of the core? it maybe worth testing this using IPSLA on the router to constantly ping another router in the MPLS core and when it happens you can see if that stopped working aswell..
Let me know if this doesn’t make any sense as I am not the best at explaining my thoughts..
All the best mate