Version: 5.2.1.2
Build ID: 31dd62db80d4e60af04904455ec9c9219178d620
CPU Threads: 4; OS Version: Windows 6.2; UI Render: default; 
Locale: en-US (en_US); Calc: group

Index marks not saving - lost index on two major projects because there is no way to notice that this is happening and so backups become corrupt.

To replicate
1) Open Writer create new file and add some text
2) Add index marks - check they are there with field highlighting
3) insert index - works
4) save file odt, close writer
5) open writer - index marks gone not highlighted
6) update index - all entries gone

Uninstalled and did a complete reinstall from fresh download - same behaviour.