Knotthead,
Just the fact that a stock passed the MA50 is not guarantee that it will stay above it, in the case of ABR, the stock is in accumulation and that was just a little more buy pressure, in the case of ACAS, it was a rebound due to oversold situation, but, after cross the MA50, the stock had several indicators in overbought level, ADX and RSI, and the price needs to correct, it was just profit taking.
T/A is simple, but, at the same time a little complicated because you need to use several indicators, not just one.