Different clients have different settings. When prerolls were first introduced at least one trailer had to be selected but you could get around that by disabling the three cinema trailers options.
Then client got out of parity at some point. Where android and web I think forced the trailer regardless of the number of trailers set while other still had the need to set it to at least 1.
Then Roku had another version we were checking out and that team added the “pre roll only” option which is default. As far as I am aware the end goal for all clients is to have the “Preroll only” setting and it be default though I don’t know when that will happen.
This current bug is obviously making all clients behave a wacky and is exacerbating confusion due to the apps not being in parity
