I tested it a bit more and these are the results:
1. I started with 'Allow reaction only for selected members' and enabled the Unique Reaction, but I was able to use it multiple times. (I removed each react after the test)
2. I then switched it to 'Disallow reaction for selected groups or members' and tried to make a react, but it told me I was only able to do it once per day and did not let me use it. (I had removed all the reacts, so it must have an internal memory of when it was used). The 'Disallow reaction for selected groups or members' option also has a flaw, which is why I never use it. A user can copy/paste the url to the react and use it, even if they're not supposed to. This is why I ONLY use the 'Allow reaction only for selected members' because it doesn't allow people to use it that are not supposed to.
3. I then TURNED OFF Unique Reaction, but I still can't use the react, now it says 'Sorry, there was a problem reacting to this content' when I try.