ib4t "your sample size is not big enough".
There's a huge thread on this. It's obviously a bug. Neither the community nor the dev team will acknowledge.
It isn't "obviously a bug", just people who fail to realize that 20% chance does not mean that you should get 1 critical every 5 RE's.
If you are a gamer and have access to a D10, try a little experiment. Pick any two numbers on that die and start rolling. Keep track of how many rolls you do and keep track of the times you land on one of those two numbers. I can guarantee that you'll run into long streaks where neither of those numbers is hit and that the 20% chance you have to hit one of those two numbers will not be the percentage of times you hit those numbers for small sample sizes.
Now, if you devote 10 minutes a day doing that and keep track of all the rolls and hits and do that for a few months, you'll start seeing the percentage of hits getting close to 20% and the longer you do it to closer to 20% you'll get.
The only thing wrong is that you had a couple of streaks of bad luck. We've all had it. I just had Tano craft 5 Mk-9 kits while I was offline a week ago and when I logged back in he crit'd on all 5 kits that I queued up. I've never seen that before and don't expect to see it again but I'm not blaming the RNG.