Created attachment 156706 [details]
The attached documents contain macros. To examine the problem, you need to enable macro execution.
Open the document and allow macros.
Select the shape.
From the library of the document select makro "mail" and run it.
You will notice, that rotation works, but not vertical or horizontal flip.
To verify, that it is a problem for custom shapes, you can draw a Bézier-curve for example and apply the macro to the curve.
In case you have questions about the macros, please ask.
Created attachment 156707 [details]
Created attachment 156708 [details]
rotate by 30deg
Created attachment 156726 [details]
Example of mirror by matrix in file format
The error is visible too, if the draw:transform attribute contains a matrix, which specifies a reflection.
The attached document contains two shape, which have the same geometry. Only that in the draw:transform attribute of the blue shape, the operation "matrix(1 0 0 -1 0cm 0cm)" was added. That results in a mirroring on the x-axis, which is the upper edge of the page on screen.
A patch is for review in https://gerrit.libreoffice.org/85670
Regina Henschel committed a patch related to this issue.
It has been pushed to "master":
tdf#129532 tdf#98839 fixes for mirror of custom shapes
It will be available in 7.0.0.
The patch should be included in the daily builds available at
https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More
information about daily builds can be found at:
Affected users are encouraged to test the fix and report feedback.
Still no daily build for Windows for testing. But my work here is finished for now.