Unfortunately, it seems very much as if the SL based Evade Nanos are not supposed to stack, intentionally.
The reason why the MA line doesn't, while the Fixer line does, is because the MA line is the same as our normal Evade Buffs. The line can be found
here.
The Fixer nanos however(GSF+SL Nanos) are on seperate Nanolines, so they can stack. The old Fixer Nanos are on the same line as all the MA Nanos, while the new Fixer Nanos are
here on a new line.
Unfair imo, and has been taken up several times but there has been little response afaik.
__________________
I'm a runaway train on a broken track,
I'm a ticker on a bomb that you can't turn back this time,
that's right, I got away with it all and I'm still alive