iPad not posting to shared album

I've been sharing photos on various albums for nearly a year with no problems.

Suddenly it has stopped working properly.

When I share a photo from my iPad, I cannot see it on my iPhone shared album and no one else can see it either on that album.

If I share the same photo, using my iPhone, I can see it on my iPad album and others can see it too.

I've checked my settings and all toggles are set to green.

I've rebooted my iPad.

Any advice on how to fix this would be greatly appreciated. Thanks.