When a document has a section like this:
<text:section text:name="Section0" text:condition="ooow:true" text:display="condition">
the section should be hidden. The ODF specification says about text:condition on text:section:
The text:condition attribute specifies the condition under which a section is hidden. The condition is encoded as a string. If the value of text:display is condition, the text:condition attribute shall be present.
The expression ooow:true is specific to LibreOffice and not standardized. On loading a document with the above fragment, the section is shown and not hidden. Also pressing F9 to evaluate the text:condition expression does not hide the paragraph. (Since this evaluation is cheap, it would be preferable that pressing F9 is not needed).
This document demonstrates the issue and has the above fragment:
When saving the document after pressing F9, ooow:true is replaced by ooow:0. This is wrong and this is the bug. Also, when the initial string is ooow:1, it evaluates to ooow:0 when pressing F9.
I confirm the bug but I close as duplicate of 55814 (oldest) in which I precise the context
*** This bug has been marked as a duplicate of bug 55814 ***