You must have gotten extremely lucky. I've never experienced a rate anything near that. Even since the Season 6 'upgrade' to the drop rate.
I've run 254 STFs, and just finally got the last piece of the 2nd space set (so have MACO and Omega MK XII sets). Of the ground stuff, I've received a single piece, from KAGE. Granted, haven't run Infected a ton, as it's annoying. CGE I've run a million times, and never gotten ANY drop, blue or purple. Getting pretty annoyed at that one, i can run it in my sleep at this point, and there's just no reward coming for me.
So, of my 254 runs, I've gotten the 6 space ones, plus an extra shield and deflector. And just the KAGE ground piece. 3.5%, or one every 22 runs or so...
Blue ones are even hit or miss. Probably have 5 of the CSE blue engine, collected and stacked while waiting for the final purple to hit.