I've been using my Venue 8 quite a bit lately.  It seems the more I use it the more the glitchy issues appear.  Black boxes on websites followed by freezing and then the need to force a reboot.  This issue appears no matter what browser I use it seems.

Possible fix/work around:

At the first hint of the black box issue, go immediately into

Settings->Storage. Touch the storage graph and clear the cache.

This seems to prevent the tablet from ultimately freezing and crashing.

A cache cleaning app that can automatically clear the cache might make this issue disappear all together.  I haven't tried that yet.