Robot Framework if-condition fails

Why does is this if-clause not true when ${orderrowlist} contains data (it is a list of lists)?

${orderrowlist}=  Run Keyword If  '${orderrowlist}'== '${EMPTY}'  Set variable  ${tmp}

I log orderrowlist just before this if as well as directly after. The first logging list the expected data while at the second logging the content of orderrowlist is replaced with the content of tmp