I haven't had any big problems myself with the rolls and have missed plenty >80% but also hit several of the (few) <20%. What I know from these discussions from other games with random chances to hit is that many players get a screwed perspective of outcomes as they are very unlikely to take a shot at the low chance ones at all, hence they almost never experience the "lucky" hits.
That is not the point. A random number generator by definition generates random numbers resulting in this use case in lucky hits / missed chances. But if you realize that there are patterns in the actual realized random numbers there need to be a check in the code.
However, for random chances in games where you tend to save and reload encounters a lot one of the first things that is interesting is; when is a new seed generated and how/for how long is a seed stored. If a seed is stored in a save and a new one not generated in some interval then there is a big chance you will see similar results to actions when you reload.
You can fix this seed problem with frequently generating random seeds, but without knowing if there is an issue and what is the reason for it, everything else is just speculation. I just want to highlight that there are patterns and someone with access to the code should have a look/ do some analysis.