From Diablo Wiki
Rubber banding refers to the abrupt bounce back players see when their characters become desynched from the server. A player directs their character to another location, before the character abruptly bounces back to their starting point. This is a very frustrating and potential fatal problem, as players think they are escaping danger, only to suddenly pop right back into it.
This effect is most often seen with fast movement skills such as Tempest Rush, Whirlwind, or Strafe and the visual effect of bouncing back to the start, moving again, bouncing back again, etc, gives the term its name.
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Rubber Banding Fixes
Most players report major improvements in this issue since launch, but it continues as a problem for some.
The reasons for rubber banding vary widely; it's more often due to a player's connection or computer issues than anything in the game itself, and players may differ widely on how often they see it, if at all. A lengthy explanation of the issue was posted by Diablo 3 community manager [[Lylirra] in May 2013:
Again, we know these fixes may not resolve the issue for every player, but they should help reduce the occurrences of rubberbanding, and lessen the effects should rubberbanding occur for most players.
Now the important thing is that we're still working on these issues -- just because we implemented some changes that we hope will make the situation better doesn't mean we've called it day. So, if you're still experiencing rubberbanding, here are a few things you can do.
First, you can try performing the following troubleshooting steps to ensure that external causes are not adding to this issue (this isn't required, but recommended):
1. Ensure that your network connection is optimized.
2. Make sure that no other program is interfering with the game by running in a Selective Startup.
3. Check for updates to any drivers.
If those steps don't help -- or if you've chosen to skip them -- please let us know so we can continue looking into this issue by posting in the Bug Report forum (and be sure to check out this guide on reporting: http://us.battle.net/d3/en/forum/topic/4926752662). That's really the best location for those types of reports, as it'll allow our QA representatives to document them and forward them on to our development team for additional review.(We want your experience in the Diablo III to be as fun as possible, so working on these issues is important to us. That also means we're extremely grateful for any reports receive that can help us troubleshoot -- so thank you to everyone who's already posted!)