So, what is the question?
From the message alone I would interpret this as:
on port-channel5 a router is reachable as DR (= designated router) for multicast
the designated router was 10.10.1.2 and has now changed to 10.10.1.3
this could be another router (HSRP?), but could also be the another address of same router
You need to make your question more specific and give more information about your environment
