When was the observer effect (physics) first observed?

It seems to have been first formally stated by Heisenberg in 1958 his
book "The Physicist's Conception of Nature" but I would have thought
that it would have been noted earlier than that.

The reason I'm asking is that Teilhard de Chardin effectively
describes it in his foreword to 'The Phenomenon of Man' - "Object and
subject marry and mutually transform each other in the act of
knowledge; and from now on man willy-nilly finds his own image stamped
on all he looks at."

Teilhard wrote that somewhere in the last 1920s/early 30s which more
or less coincides with the early days of QM. I'm wondering if Teilhard
was reflecting what those involved in QM were already talking about or
whether he arrived at this under his own steam.