My first thought was a bad cap top or clogged pump tube but since all the nozzle are perfect except for cyan and yellow, I'm leaning more towards a bad damper or the head is damaged internally. If the dampers are older than 1 to 2 years old, that would be the more likely reason. If the damper doesn't fix it, the head is probably damaged internally. The cyan is getting into the yellow which either means the cap top isn't draining properly, the damper is not regulating the pressure properly, or the barrier between the channels has broken and the ink is mixing.