it has had to happen vs it has had to happened

Some examples from the web:

• What's destined to happen will happen.
• The deaths that happen, have to happen.
• But before it happens, something else has to happen.
• Nothing happens that you don't want to happen.
• Whatever she wants to happen... Happens.
• You allowed all this to happen.
• Like watching an accident about to happen.
• It's an environmental disaster waiting to happen.
• Matter is just energy waiting to happen.
• And then something monstrous began to happen.
• This obviously has to happen through our Members.
• Whatever's going to happen here needs to happen right now.
• So, if it's supposed to happen, it happens.
• You want something to happen, I can make it happen.
• I want it on its way to Charlestown before whatever's going to happen here tomorrow happens.
• And as it happens to each of us, so it began to happen to our civilization in the 16th century.
• Too many people go through life waiting for things to happen instead of making them happen.
• But whatever's going to happen will happen soon.
• If anything's happens, it's going to happen there.
• For a transit to happen, it has to overtake us, but that only happens once every 1.6 years.

Some examples from the web:

• About the biggest thing to happened in Glenwood Bay.
• Things're... when everybody's ready for that to happened.
• What's going to happened to you if he's gone down?
• What happened last night has never happened.
• Then we can agree what happened never happened.
• Whatever happened to these power lines happened after the snow monster.
• Whatever happened to them happened to Andy.
• Whatever happened to him may have happened to other crew members.
• What happened between us shouldn't have happened.
• So whatever happened happened at that party.
• Everything they say happened, happened.
• Mia, whatever happened- Whatever you imagine happened...
• I'm saying what happened happened.
• Maybe what happened to our two victims also happened to his mother.
• We think what happened here happened everywhere.
• Whatever happened, it must have happened quickly.
• What happened to him could've happened to any qualified pilot.
• What happened was just something that happened.
• Whatever you think happened last night didn't happen, because nothing happened.
• Things happened there which should not have happened.