Is this a sample application or your own? Is the GATT DB well-formed (no errors if the structure, especially if you hand-coded it)?
This is my own application.
Such message was popping up after crash when I tried to use OOB pairing with encryption in my application.
My application can work well when OOB pairing is not enabled, but it crashed every time when the OOB is enabled. That's why I am trying to check if any possibility to have deep analysis from the log message.
We spoke to the developers on this one and they believe that the problem is that your GATT DB may not be formed correctly.