Happens with my set up and been so for a number of LR iterations. Found best way to clear it is to restart LR which suggests it's a cache related issue.
Same problem here with Mac OS Sierra 12.4 and LR CC 2016 2015.10 Everytime I resize or move the map in map module I get a 3 second blacked out map and an error window Map Offline and then map is back to work. It all started 3 days ago out of the blue. Please research and fix. Its very annoying.
I haven't been using Lightroom for a week or so, but this was not happening to me when I last used it. Now it is happening big-time (and, boy, is it annoying).
Lightroom 2015.10.1 Camera Raw 9.10.1 MacOS 10.12.5 iMac 5K 27 inch, late 2014
Also have the problem. I'm running Windows 8.1 and Lightroom 6.10.1, build 1117303. I first noticed the problem yesterday after a big Windows update, but this might be a coincidence.
I hadn't updated Lightroom until after I noticed this problem - I hoped it would cure it - but I'm not sure of the exact version I was running before. Everything else on the laptop seems to be OK. The broadband connection's fastish, but pretty reliable.