There have been various permutations of this issue. In this case, a BB holder parked in a bay showing the road marking DISABLED and displayed their BB as required.
They're being penalised because they're not a permit holder of the type specified in the sign.
We've seen BB holders penalised because they parked thinking that the term 'disabled permit holder' applied to them and they've lost at adjudication. But here a blue badge holder parked because the bay was marked with a term which applies ONLY to BB holders and has no relevance to 'disabled permit holders'.
IMO, this has nothing to do with the upright traffic sign, it's the road marking.