Which version of Lightroom and Bridge are you using?
Do you have the option "Auto rotate "turned off in your Camera?
Did you Exported these Jpegs from Lightroom or any other editing tool?
Also in Lightroom Do you see Auto Straighten /Crop Angle in the History Panel?
There is no such option of Auto rotate in Bridge
What happens when you Uncheck "Use Graphics Processor" in Bridge(MAC:-Bridge>Camera raw Preferences,Windows>Edit>Camera raw Preferences)
Thanks for responding so quickly. In answer to your questions:
Both Lightroom and PS are current, subscribed CC2015 versions
Images are not rotated in or out of camera. All such options are permanently off.
Imported directly from camera however some of the images are already 3 years old! It is only now or of late that this has started happening to the same images that previously were ok.
No history in lightroom - I can open the same images in at least two other software systems with no such effect
Unchecking "Use Graphics Processor" results in the same thing.
What happens when you selected an image that has been rotated/Skewed and then click Reset in Lightroom Develop module?
Does it change the image skew?
Try to Reset Lightroom Preferences
Then Create a new catalog in Lightroom
And import these Pictures again to check if they are still Rotated.
Share few of those images(specially the one's rotating) with us using (Dropbox/Wetransfer etc..)
We will check if the issue Persists
Will do so shortly. 9pm in Aus and family responsibilities call!