SNMP not polling

I have 2 RB800’s running firmware version 5.14 I am trying to set up some polling for rssi levels, data, cpu usage, ect…All of the OID’s for information on the routers are fine…I can pull name, location, routing table, ect…however when trying to pull the above, signal, data , cpu usage, ect…I am getting an error “Variable has bad type” Is this a firmware issue? or is something else awry? I have a couple RB433’s that poll just fine along with numerous 750’s. Thanks