thanks. Your calculation is rather strange in form since the complex exponential of a commutation superoperator would normally be calculated for the case of a Hermitian operator, i.e. superoperators of the type Exp[-I CommutationSuperoperator[opI["x"]]] rather than Exp[-I CommutationSuperoperator[opI["+"]]] (note that opI["x"] is Hermitian, while opI["+"] is not).
I suspect that the perceived problems are something to do with your choice of a non-Hermitian operator, although I do not yet know how this works out to give the behaviour you show. It is possible that the behaviour is expected for such an unconventional calculation.
Please verify that you really want to calculate the term shown.
As an additional comment, when posting a bug, please indicate clearly what behaviour you find to be unexpected or wrong. That will save effort on my behalf.