What strange values, specifically?
This is frequently caused by altering the default values. In Develop module with a problem image selected, try this:
First, at lower right of Develop Right Hand Panel, click the 'Reset' button. Does that fix the problem? If so, we'll need to know more about your import dialog settings probably.
If not, press and hold the Shift key, and then press 'Reset (Adobe)'. Does that fix the problem? If so, somehow your default settings have been changed. Press and hold alt/opt, and press 'Set Default...', in the resulting dialog, choose 'Restore Adobe Defualts'. Note you're also offered a chance to change the default to the current image settings, which is likely where the problem began.
If this is off the mark, let us know.....