I seem to remember a while back many moons ago a support case where a particular Cisco OID had a suffix issue (it was either required or you needed to drop it). I have a feeling it may have been relating to serial numbers.
Try dropping the last .0 from the OID and see if that fixes it. If not then try appending a .0 or .1 to the end.
It was a while ago, so things may have changed... but I'm fairly certain it was related to getting Serial Numbers.
Please post back if it works!
Also try 188.8.131.52.184.108.40.206.6.3
Now that look familiar. I think this may have been the OID which needed the .0 appended.