RT-N66U web admin (https) hangs

[ang_mor]

Using 378.55 (?) and today 380.58, web admin (https) hangs when switching from the main menu to other screens such as "Advanced Settings"\"Wireless".
There are two ways around the problem:

1. In the browser, click on Stop loading, and then Refresh.
2. Use http instead of https

I have tried this from multiple browsers over time: IE, Firefox, and Iron. After I loaded 380.58 today, I only used Iron.

Any ideas why this would happen ? Browser settings issue, Merlin bug, or ???
--
Brian