Looking on the internet deeply has found these results:

This should not be happen is the most popular phrase on the web.

This should not be happened 116,700 results on the web	This should not be happen 140,700 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
This should have happened a long time ago under better circumstances. This should have happened a long time ago under better circumstances. I think this should actually have happened months ago Okay? None of this should have happened. This should've happened lifetimes ago, and... None of this should have happened. incidentally, the first Commission communication dates from February. You know none of this should ever have happened.	upgrade or install. This should not be allowed to happen again. But this shouldn't happen tomorrow. This should not happen in Europe. More common in neaonates and may be happen in young children too This should only happen during dist In today's world where everything happens suddenly shows the sign that anything could be happen to anyone. I think it is most necessary that we as the European Union say that this should not be allowed to happen in a country that currently holds the chair in the Council of Europe's Committee of Ministers.

This should not be happened

116,700 results on the web

This should not be happen

140,700 results on the web

More popular!

upgrade or install.
This should not be allowed to happen again.
But this shouldn't happen tomorrow.
This should not happen in Europe.
More common in neaonates and may be happen in young children too
This should only happen during dist
In today's world where everything happens suddenly shows the sign that anything could be happen to anyone.
I think it is most necessary that we as the European Union say that this should not be allowed to happen in a country that currently holds the chair in the Council of Europe's Committee of Ministers.