I am having a similar issue with "Win 5 Greater Force Potions from Stage 7 or higher of the Force Keep."
I have farmed 4 greater potions yet I remain 0 / 5. Between each, I have restarted the game and even changed devices but the counter remains 0.
um91385236 | 88572377
After the 4am PDT reset (Clan boss, etc) I received credit for my: 4 / 5. However, I ran a few more times, received 1 more greater, and did not received credit for the last. Perhaps there is a delay or something else but it's still not working propely.