Hi @andrewatfornax,
No, it's definitely not caching. I've reduced caching time to 1 second for banners, also every other change reflects immediately. I tried deleting the cache manually by clearing /var/cache folder entirely.
I checked the plugin code, it sends the bannerid request for companion banner correctly to Max_adSelect function but returned value is {"html": ""}, the banner has html value correctly and appears fine when directly configured with a zone id, just doesn't come as a companion banner for vast tag.
Not sure what exactly is going wrong here. Please help.