Description:
The page count fluctuating with a possible difference of 14 pages between file openings

Steps to Reproduce:
1. Open attachment 151991 [details]
2. Wait until file loading finished & scroll down. Click the last page
3. Close the file & reopen it from start center 

Note: File reload will work the first time.. but the results of the next attempts are always the same.. layout caching I guess.. Close & reopening from start center will give better results

Actual Results:
* Initial 306 pages [probably saved within the ODT, but horrible wrong]. Steps to create a situation like this rather easy. Open the attached file. CTRL+A & CTRL+C & CTRL+N & CTRL+V -> Look at the page count & Save 

* The page counter is correcting itself. The 306 will change to something else after brief moment

* When scrolling down & and clicking the last page -> The page count shown decrease by 1 [at least in most cases I know of when working with large documents & footnotes)

* The number of pages will fluctuate between 288 - 302 pages. It never worked perfectly, I'm admitting that. But Libo 4.4.7.2 was only 1 or 2 pages off; not 14

Expected Results:
Page count should at least be more accurate


Reproducible: Always


User Profile Reset: No



Additional Info:
Version: 6.4.0.0.alpha0+ (x86)
Build ID: ac14e5613597e7361ce6995dacb1bb5bd55b6b00
CPU threads: 4; OS: Windows 6.3; UI render: default; VCL: win; 
TinderBox: Win-x86@42, Branch:master, Time: 2019-06-06_05:09:49
Locale: it-IT (nl_NL); UI-Language: en-US
Calc: threaded