105 Shimano 10 speed shifters - compatibility with 11 speed rear derailleur I am building a bike and I am using 10 speed Shimano 105 shifters.
On the back I am using a 11 speed 105 rear derailluer (because is the only one I have at the moment).
The cassette I am using is a standard SHIMANO TIAGRA CS-HG500-10 10 SPEED CASSETTE 11-25T.

Unfortunately, I am having some problems: when in biggest cog or second one, the chain moves out of the tension pulley and gets stuck (by the way the chain is a 11 speed chain, so width should not be an issue). 

Does it seem like there could be something wrong with the chain line? 

Any of you knows why it happens?
Did it happen to you?

Thanks already for your input!
This is to do with the different pull ratios employed by the different systems.
In your case 10 vs 11 speed Shimano.

http://blog.artscyclery.com/science-behind-the-magic/science-behind-the-magic-drivetrain-compatibility/

If you look at the table in the link - it says the 10 speed levers pull less than the 11 speed levers but the rear derailleur ratios are also vastly different.