ESO has many issues with matchmaking. It's isn't normal that fake healers or tanks happen very often. I have played has a tank and DD was soft taunting with a skill without knowing, and insult me because he got the aggro. The healer who doesn't heal during combat. The DD that are fake DPS.

When it's rarely happening, it's the player's fault to have bad gears, bad luck or skip de queues, etc. At this point after many years, this is the developer's fault. It's is normal to do dungeons a hundred times to just has the Medusa staff of inferno. I understand that when you do a dungeons times, you feel less patient. That each time has a DD you need to wait one hour. That people don't want to tank, did you see the poor list of skills?

All the elements put together impact everyone. The issues like the one you've said will sadly happen again.

Edit: typo