Well, according these reports:
Maps not rendering street names properly
Mysterious ugly rectangles
-
I've updated my Google Chrome and now the problem is fixed.
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Yesterday downloaded latest version of Chrome, today I went to maps to
check something and all labels were rendering just fine - no
rectangles!
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With the latest update they fixed this strange problem.
-
Yesterday downloaded latest version of Chrome, today I went to maps to
check something and all labels were rendering just fine - no
rectangles!
As I wrote in the comments, I had the same issue, and yesterday (after
the new google-chrome version update) it started to work properly.
So I'll suggest you to try to update your chrome browser, and hopefully it'll be fixed for now.
To update your actual softwares (including google-chrome), you can type:
sudo apt-get update && apt-get upgrade
Or
You can type software updater to the dash, and select like this.

The current version what I have after the update:
google-chrome --version
Google Chrome 55.0.2883.75
I hope it helps you to solve your problem.
chrome://flags/
? like: Accelerated 2D canvas, Display list 2D canvas, Overlay Scrollbars, LCD text antialiasing, Distance field text. You better report this as bug report. Do you find same issue with Chromium? – user.dz Dec 6 '16 at 7:22