The official answer is that Star San solutions should be clear and a pH below 3.5.
If you used Distilled water the solution would not turn cloudy. The product can react with hard water and turn cloudy. The Minerals in the water can react with the anionic portion of the star san and cause it to go bad. Yes, when this happens you should consider making a fresh solution. The cloudiness usually forms after a dwell time or when people try and store the solution for multiple weeks. If this is the case then, yes always start with a fresh solution.
The conventional wisdom is that Star San is good below pH 3.0. Apparently conventional wisdom never read the label.
Phosphoric acid 50%
Dodecylbenzenesulfonic acid 20%
The second ingredient is a detergent that reacts with calcium or magnesium to form a cloudy precipitate. This is the slime that sometimes forms when people soak stuff long term. It comes from hard water, the vinyl is not dissolving.
No worries about your cleaning products having bad reactions. The one to worry about is to never mix bleach and vinegar directly. A better plan is to avoid using chlorine based cleaners altogether.