I posted this in the Windows Bridge forum, but a camera raw preference controls this so I am also posting here.
On jpeg files without any RAW setting applied, Bridge still applies RAW settings to the thumbnails and the preview are thus display incorrectly. Opening the file shows the jpeg as it should be, without RAW settings applied.
I have RAW preferences set to apply auto settings to RAW files without any current settings.
I have my RAW settings to open jpegs in RAW *only* when they already have settings. If I set this to disable jpeg support, then the RAW settings are not automatically applied to jpegs without existing settings. aka, Bridge redoes the thumbnails without the auto setting.
While it is correct to apply auto tone to RAW files without settings, jpeg files are already "developed/printed" and should not get additional auto develop settings automatically applied.