The only explanation for this is they are intentionally scamming or there is a major bug that they have not bothered to fix. Either way it is a provably unfair game.
these are not the only explanations, and you know it!
for example some other reasonable explanations...
1. its some sort of display error - underneath its working fine
2. the roll history is just corrupt for this user - but they have really been rolled correctly
3. the screenshots are faked
im not saying any of these are definitely the case. thats because i can accept that i have NO EVIDENCE or PROOF either way, the same as you (or baby3d) doesnt have any evidence or proof.
but these are all possibilities too, and none of these 3 explanations make it less provably fair
all i do know is that baby3d has a clear incentive to misrepresent the facts as he/she has admitted that they are hellbent on destroying coinpot
this is really all just FUD being spread by repetitive posts from 2 or 3 user accounts