Hi everyone,
Thanks for your patience. We understand that this is an annoying behaviour and therefore we have a solution for you. In the latest version of Acrobat DC, you can disable the "auto convert to text".
Just open any scanned PDF and click on Edit PDF. On first launch, Acrobat will convert the image to text. Now all you have to do is click on the 'Revert to Image' button on the Right Hand Pane. Acrobat now remembers this setting and will not convert any scanned document to text unless you change it from here.