The bug

You cannot give a squid on land a horizontal Motion either by summoning it or by changing its Motion with the /entitydata command, but you can give it a vertical Motion.
Due to MC-89883 the squid might appear to be moving horizontally client-side but is not server-side.

How to reproduce

/summon squid ~ ~ ~ {Motion:[2.0,1.5,0.0]}

What this should do is summon a squid being hurled east. This works for other mobs that do not have any special movement patterns such as bat and ghasts which can fly, but not squids.

Furthermore, the squid is not rendering in the correct location. Although the squid does not move horizontally, the particle effect created from landing in 1.7 appears 2 blocks away along the direction it was meant to go.
Entity detecting blocks such as pressure plates and trip wires can also be triggered where these particles appear and not where the squid renders.