80% of the sentences are intrinsically unflippable like these examples. Many are sheer gibberish.
Since most quorans are using the forum to cheat on ESL homework, these questions look plausible at first sight.... but no ESL teacher would ask you to flip the unflippable, or deal with gibberish.
Two days ago a SMART questioner wondered if these impossible requests were actually a code.
Now we're talking sense! Instructions given to operatives who share a dictionary of keywords, or who know how to pick out the sequence of meaningful letters.
After the COGENT question, the passive items disappeared completely. Haven't seen a new one since. I don't know if the moderators started to delete them, or the posters stopped using the method.
The current icon shows Polistra using a Personal Equation Machine.