A.I is still very much being tweaked, so any good step by step (pardon the pun) to show me a clear issue with stock media from the core product will help me reproduce issues that are clearly 'not clever' for the AI to perform. There is a fixed step height in the physics system for characters to climb stairs related to the 'capsule nature' which is partly defined by their radius, but there may be other solutions to the core issue you have which involves getting characters up and down stairs sensibly.
PC SPECS: Windows 8.1 Pro 64-bit, Intel Core i7-5930K (PASSMARK:13645), NVIDIA Geforce GTX 980 GPU (PASSMARK:9762) , 32GB RAM