IF expression on NULL item mixes up then and else

[Oliver2 (Oliver)]

Edit: yes, didn’t see the forest: it has to be 'NULL' instead of NULL.
I do not delete this post, just in case anybody else does the same mistake… /end

I probably do not see the forest for the trees…
Item state is NULL

when building an expression with “IF” I get the wrong result:

double check: replacing === by !==: