so you started as thief for 4 levels, taking spell sniper [with eldritch blast] and then mulileveled into warlock for 2 levels?
if so the E-blast is a thief spell and should be listed there i.e, under thief... if its not then yes this is a bug so report it and include a save file with the missing icon
p.s, as a workaround you can pay 100g to respec in order to keep playing
