IF_Index are being removed?

I'm adding in a Cisco 2600xm frame relay router, when I first add it, it shows up with all 51 Indexes, then I rename its display name and set it to be a router (Instead of a switch) and after a few pulls indexes 17, and 19-35 (18 still shows oddly) go missing. 17-35 are my PVC's (Serial0/0.DLCI) all are UP and active and I can browse to them and monitor them with other SNMP tools. I have a standby 2600(not xm) at the same site with a simular config that I can pull and all Indexes are shown and are down ofcourse. (it has 36 indexes)

My 3640 shows its 10 pvc's properly. I've deleted and re-added the 2600xm and show the same results each time. Is it possible that this is alimitation of the # indexes it can display? I can see all 260+ on my 6509.