Drowned not taking damage when underwater

When attacking a drowned underwater, they practically swim right through me and when im attacking them, they wont take damage until ive swung my sword 4 or 5 times, yet ill take damage as soon as they swim up to me. Ive also seen many drowned, especially the ones with tridents, get stuck in a block and spin in circles constantly until you get close enough for them to lock onto you.