The term "Tip Stall" originated with the glider groups of the 70's and is a misnomer. There are several type of stalls, but a "Tip Stall" is not any of them. A forward stall with a straight ahead break can be an approach or a departure stall. When one wing stalls, it is usually called an accellerated stall. Generally due to the increased AoA of one of the two wings. All of them are caused by increasing the wings angle of attack until airflow separation occurs. This can happen at any attitude and airspeed, which is one of the reasons the admonishment of "keep your nose down in the turns" came into being.

A heavy wing on one side of the plane will create the need for additional aileron trim to counteract the force of gravity for that wing, increasing drag. At the correct airspeeds and attitudes, this aditional trim induced drag will induce a stall for the one wing.

A sudden breaking out of a maneuver is called a snap, or cross control stall, and is caused by excessive or incorrect use of the controls. It's actually an accellerated stall, with an over the top break.