So even Lifepaths is busted when it comes to Mysads. Why am I not surprised?

Seriously, Mysads are really not
that hard to balance acrosss all the different chargen methods - as long as you are willing to limit their potential to a reasonable degree, that is. Just give them only
half their Magic in PP (no rounding needed, PP are valuable in Fractions as well) and only 1x Magic (i.e. half of the spells a Full magician gets) in Starting Spells. Take away the option to Initiate for 1PP and confine them to getting their PP by increasing their Magic Attribute (or by using KI Foci) - and of course, they only get 0.5 points for each Karma-bought point of Magic as well.
Maybe give them Astral Vision without Adept Powers, if all that sounds to punishing. Mysads are supposed to be a "blend" of Magicians and Adepts, so why not just make that blend more or less 50/50 all they way? No confusing separation of priorities/points/path-based Magic and Karma Progression needed.