For a root vegetable such as sweet potato, taro (actor -um- & patient) to become only partially cooked, due to insufficient fire.
Agguy nalūtu han lapnay ti immāhol ti agguy nihulnud.
The sweet potato was not cooked, it became only partially cooked because (the fire) was not stoked.
For someone (agent) to allow something being cooked (theme ipa-, -on), as a root vegetable to be only partially cooked, as by allowing the fire to die down, taking it from the fire too soon.