Description:
Work on an impress document.
Doing more changes. I save the document and immediately thereafter making a save us with a new name of the document.
Close them.
At opening both last saved versions lost the last changes I made in the document.
It seems the save was not effective and only a few (more) minutes earlier versions were saved.
It did happen in the last 3 days already 3 times.

Steps to Reproduce:
1.Make more/many changes in impress copy or write texts in texbtoxes
2.save it
3.make thereafter a save as with a new name
4. both last doc lose last changes has been made.

Actual Results:
Nothing. It seems both the save and also the save as action was made without any error or difficulty. There is no special sign that failure happened.

Reopen any of the last 2 versions and some changes are there and some are disappeared.

Expected Results:
Keep all changes I made before the saving. As it is the normal expectation and it works many times.


Reproducible: Sometimes


User Profile Reset: No


OpenGL enabled: Yes

Additional Info:
Version: 6.0.7.3
Build ID: 1:6.0.7-0ubuntu0.18.04.10
CPU threads: 4; OS: Linux 5.4; UI render: default; VCL: gtk3; 
Locale: de-DE (en_US.UTF-8); Calc: group


OpenGL vendor string: X.Org
OpenGL renderer string: AMD RV620 (DRM 2.50.0 / 5.4.0-65-generic, LLVM 10.0.0)
OpenGL core profile version string: 3.3 (Core Profile) Mesa 20.0.8
OpenGL core profile shading language version string: 3.30
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile
OpenGL core profile extensions:
OpenGL version string: 3.0 Mesa 20.0.8
OpenGL shading language version string: 1.30
OpenGL context flags: (none)
OpenGL extensions:
OpenGL ES profile version string: OpenGL ES 3.0 Mesa 20.0.8
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.00
OpenGL ES profile extensions: