The quest (id: TR_m3_FG_OE_ChampLost ) leads to Munamnabi cave where you're supposed to find a note... ( According to https://en.uesp.net/wiki/Tes3Mod:Tamriel_Rebuilt/A_Champion_Lost ) I did not find it, I even looked everywhere with TCL command... I also confirmed the quest worked ok after typing "player->additem TR_m3_OE_FG_bk_ConJou1 1" to console and reading the note.