Often I use my tablet inverted in portrait mode (charging cables, etc). Joplin is fine here. When I invert my tablet, Joplin display inverts.
However if I make a text selection from another app (mail, browser…) while vertically “inverted”… and select “Share” and then “Joplin”, the shared text displays in Joplin, however Joplin ignores the tablet orientation and will not change from the default portrait orientation.
I tested this against Google Keep and its window orientation matches the shared source.
I’m using a Tab A with Android v9.