Given a propositional formula $\phi$, then positive/negative occurrence is defined as follows
$\bullet$ $\phi$ occurs positively in $\phi$
$\bullet \neg \phi_1 $ occurs positively [negatively] in $\phi$, then $\phi_1$ occurs negatively [positively] in $\phi$
$\bullet$ if $\phi_1 \land \phi_2$ or $\phi_1 \lor \phi_2$ occur positively [negatively] in $\phi$ then $\phi_1$ and $\phi_2$ occur positively [negatively] in $\phi$
Assuming that the set of operators is $\{\land, \lor,\neg \}$, can we say that polarity of the atoms (positive/negative occurrence) is uniquely defined i.e if $\Phi_1$,$\Phi_2$ are equivalent formulae then the polarity of their atoms is the same?
Initially, I thought this is obvious because I could convert the formulae in negative negation form and all atoms occurring negatively are negative and all occurring positively are positive (also they can occure both ways in the same formulae ). But I was assuming that NNF is canonical, but then I realized it's not, and hence the question.