Libreoffice calc - cannot change the size of font in all cells simultaneously

I have the same issue as that question: Change font size whole sheet Libra calc?

You could say this is a duplicate but his solution does not work for me. Also, no one replied to his question.

I cannot change the size of all the cells at the same time (with ctrl+A and changing font size), some cells change their size others dont and I need to manually chage the size of the font in each cell:

I even tried to remove the formatting (everything except text and numbers).

Isnt this a bug?

Version info:

Version: 7.4.6.2 (x64) / LibreOffice Community
Build ID: 5b1f5509c2decdade7fda905e3e1429a67acd63d
CPU threads: 16; OS: Windows 10.0 Build 22000; UI render: Skia/Raster; VCL: win
Locale: el-GR (el_GR); UI: en-US
Calc: CL

Would you share a file to test? The green and bold text in the screenshot shows that direct formatting was not cleared.
Just two guessings: It could be conditional formatting (menu Format), or Shrink to fit cell size (Alignment tab in Format Cell dialog).


EDIT:
One more: The cell content was formatted while in edit mode.

That excludes my two first guessings: conditional formatting and shrink to fit cell size.


The file was saved always as .ods?


Ctrl+M (menu Format - Clear Direct Formatting) could help here (this is mentioned in the question linked).