Ok, retested client side resizing with EXIF oriented images as landscape and portrait. Works perfectly fine. I'm not sure what to suggest beyond disable client side resizing. You both appear to be using iPhone. Please try uploading those photos to your cloud, download them onto your computer, then try uploading them. If issue persists please PM a URL to the raw image that I can download and test as all my test EXIF images are working fine.
Please note the latest CB Gallery update was 3 months ago. So it's odd this would suddenly be happening now and suggests a problem with the device. Did your iPhone update recently and then this issue started?
You can find the images I use to test orientation below if you want to give them a try as well.
github.com/ianare/exif-samples/tree/master/jpg/orientation