Makes me nervous to see the fix is to remove the maxValue variable, but if it works, ¯\_(ツ)_/¯. I'll give this a try in a bit.

Yep, I confirm, this fixes the issue.

PiRngWrapper in this file provides what the standard calls a UniformRandomBitGenerator - i.e. std::shuffle just wants a random integer in the inclusive range [ PiRngWrapper::min(), PiRngWrapper::max() ] and will take that integer and generate a random index into the shuffled range itself. This is the computationally simplest method of addressing the bug and removes a superfluous modulo operation.