Hey there. Up until Tuesday's patch, the rotation was broken in some regards, namely the frequency and the rotation times were not in sync with the daily or weekly resets. So mods were easy to miss. This was fixed on Tuesday. I believe there are 4 available mods (Enduring Wells, Seeking Wells, Bountiful Wells, Supreme Wellmaker) in that reward slot, so if it was not tuesday's, yesterday's nor today's, it should be there tomorrow.