Incorrect Page Count Value
It appears that InDesign CS6 or any of the later CC versions is incorrectly writing the page count metadata, such as CC2018.
This can be demonstrated using Adobe Bridge or ExifTool with the -XMP-xmp:PageImagePageNumber command.
Files consisting of 1 to 2 pages are correctly reported. In all cases, only 2 pages are being shown, whether the file has 3, 4, 128 pages etc.
Screenshots from Bridge CC2018 uploaded/attached.
There is a preference in InDesign to save preview images with document, by default ‘First 2 Pages’ is selected in that preference. You can change the setting as per your requirement. It is under ‘InDesign CC/ Edit→Preferences→File Handling’.
Thank you Uwe, I did not realise that this was the case – what you say makes sense thanks!
Uwe Laubender commented
check your preferences with InDesign. Bridge is reading out the Preview images of pages that are stored inside an InDesign document. Default is to store the first two pages. You can change that to all pages. Also changable is the size of the preview images.
( ACP )