Just going to start over!
Veneering over well adhered veneer should not be a problem. If the doubled up edge is visible, it might make a minor difference that way. Unless there are other factors, I think you'd be fine to put a second layer on.
Best practice would dictate that you'd do same on both sides so as to balance the assembly. I've ignored this rule of thumb a at times with no ill consequence, but on an unbraced panel like the top half of X Static, I think it would be a good idea, lest you get a bow pulling toward the doubled up side a month or two down the road.
Or do over, I guess, if you've already started.