There is some conflicting advice here. It seems that most people have either a favourite manufacturer or method. Personally I agree with some and not with others. However, ultimately you are looking for an answer to your problem. That is the tricky part. It could be something as silly as dust on the membrane. But generally as long as you follow the manufacturers advice and instructions most systems work. Admittedly some are better than others. Personally I prefer sheet butyl membrane to any paint on. The other thing to note is DO NOT mix different parts from different companies. If you decide to use a particular brand, ONLY use the products they supply /specify. That way if you should ever have a problem you can call them out to advise.