What is the error you are getting?
None, C::B just silently resets any start offset greater than 32000 back to this number and displays wrong part of array.
What is the output of the full debug log (You have to enable it in the debugger settings)?
I don't know yet, I have to run C::B from a terminal and check if there's any output at all.
Have you tried your use case form the console with raw gdb?
I'm not that skilled with raw GDB, sorry, I have to look up command reference.