Honestly I've never had a problem with it. The amount of N in that product is not enough to change the pH in the substrate. The only way to change the pH in a substrate is from either the type of N(nitrate or ammoniacal) or by the alkalinity of your water over time. This is why I don't think the pH issue would have been caused by the perlite.
I'll be using vermiculite in the future as it's recommended over perlite with it's silica content.
Up 'til now, with the odd exception, I've always used the MG brand of perlite.
Yup it does, and you found that out already.