Transitioning from lethal to LL is not ideal, but it works if you have rigid adherence to verified transition procedures - which requires two officers.
Of course, dedicated is the best way to go.
In the case you mentioned, was it a dedicated LL shotgun?
I'm aware of a case where the officer verified transitioned to LL, then decided on his own that he was going to transition back, when they called for LL it wasn't available. Lady went on to suicide herself.