If your cab panel is not releasing easily when you have turned the lock then more than likely your striker pin is coming into contact with your latch. Image below shows the striker pin rubbing against the latch.
To correct this issue you can adjust your striker bracket towards the cab. Crack loose the allen screws holding your bracket to the rail. You will need a 5/32" allen and a 7/16" socket for the 1/4" nuts below the rail.
With the bracket loose, slide it towards the cab roughly 1/8". Retighten the screws and then test your panel to see if it releases for you. If not, repeat the process of adjusting the bracket towards the cab until the panel releases.