Token moving across dynamic lighting layer

I have a player whose token is able to move across the dynamic lighting layer.  This is a problem that has been going on for quite a while now.  The other players are not having this issue just the one.  We are both using Chrome for our browser and the settings for his token are set up like everyone else.  The only thing that I can think of that is different is that he has control of two tokens that he sometimes groups together to move them more easily but they can move across the layer whether grouped or not.  Thanks for your help.

I've noticed a similar thing in the games I run... Singly-controlled tokens cannot pass across light barriers, but grouped tokens can and often do cross them. Then at least one token will get "stuck" in the wall and I as the GM have to pull them back onto the intended playing area.

From testing this seems to mainly occur when grouping tokens and then rotating the group, leaving the group in the original configuration obeys the normal movement restriction on a token by token basis, however if you rotate the group at any point the outlying members can potentially pass through the walls and into the restricted areas. Also worth checking is that the players token has 'has sight' ticked on their token, if they don't then dynamic lighting has no way of knowing that the rules apply to them.