Would suggest you to reset Lightroom Preferences and then, check.
Refer this article for instructions : Resetting (or 'Trashing') the Lightroom Preferences file - Lightroom Forums
If that does not help, you might want to create a new catalog and import a few images to test.
Deleting the preferences as per the link made no difference. (Same problems as listed above).
** However creating a new catalogue with just 27 photos in 1 folder seemed to work correctly:
Ex: Map module opened and metadata saved correctly.
Can I 'import' the original catalogue settings into the new catalogue - without importing the LR problems?
I want to keep catalogue data such as Stacking.
Go to File > Import from another catalog. choose your previous catalog to be imported from > check if the issue reoccurs with the previous catalog data re-imported.
The problem appears to be solved (as in disappointing need for a workaround).
Opening the original 'old' catalogue the first time after creating a new 'test' catalogue made no difference.
But opening the old catalogue seemed to work with all the issues cleared.
The problem seems to be resolved.
I suggest Adobe uses quality control. I now hesitate to recommend LR to others.
Thanks for pointing to the workaround.