RT-AC88U slow admin access and slower with Merlin firmware

I picked up a like new ASUS RT-AC88U router off of Amazon Warehouse that had Merlin firmware installed on it. Idea was to replace a T-Mobile Cellspot router I updated to be a RT-AC68U running Merlin. First thing I noticed out of the box was how slow the Admin access was. Just logging in takes close to 1 minute to refresh and paint the first screen, then switching to each new screen takes at least 30 seconds. I then did a full reset on it, but still the same.

Next I grabbed the latest...

RT-AC88U slow admin access and slower with Merlin firmware