Over the holidays I decided to build a new PC for the lab using an Intel X540-AT2 network card. When connecting to the RB201UAS-2HnD (ROS 6.43. on ports 6-10 it works as expected (max at 100Mb), however on ports 1-5 it auto-negotiates to 100Mb full but refuses to acquire an address. I tried to force speeds on ports 1-5 without success, swapped cables, verified cables on other equipment. Ran both Ubuntu 18.04 and Windows 10 with the latest Intel drivers thinking it must be a driver issue with the NIC. Finally I connected a spare RB751G to the PC and it works, auto-negotiates at 1Gb full - no issues.
The RB2011 in question has no issues connecting at 1Gbs to the RB751G, hAP ac², a windows PC with an Intel 82566DM-2 NIC, or an Asus RT-N56U.
After searching online it looks like this was a fairly common issue with the RB2011 series and Cisco equipment starting back in 2013. I ran across numerous complaints but failed to find the resolution. Did I overlook something, or do I need to keep a second switch in place?