Hello, I don't know if this has been checked but just in case, see:
a) if the layers in which the Xref are inserted are not frozen
b) if the Xrefs are visible (that the links with the source files are correct), it may be that only images (not the Jpeg, but a memorization in the drawing) are processed. In the latter case, reactivate the links.
In the paper space, type the RGT (regentout) command. This regenerates the drawing and also external references
Reload the file in question in the External Reference Manager
Check that the link refers to the correct file
Check the link type (overlay or level) Important if your reference also has references.
Make sure that the affected layers are not frozen in the windows of the paper space
At worst, detach the reference and then reinsert it into your drawing
For your second problem, I don't see where it can come from except possibly the USCFOLLOW variable which zooms in when you activate a window (you have to set it to 0 (zero).