Formatting of comments in Writer cannot be changed?

LO Writer allows me to change f.e. color or size of some comments (ad hoc). However, after saving changes and reopening the file, these changes are not saved. How can I ensure that the changes will be saved? I can understand that some changes may not be “allowed”. But here, Writer allows me to do it, allows me to save changes - and ignores them after reopening.

CPU threads: 4; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win
Locale: cs-CZ (cs_CZ); UI: cs-CZ

You posted environment info provided by LibreOffice in the About dialog; but somehow, you omitted the primary important info about LibreOffice version, that is also provided there?

Also, the file format is not mentioned.

LO 24.8.4.2 (X86_64).
I save my files as .odt.