I've been encountering a similar behavior for a long time (maybe since I've started using activities but I don't exactly remember). Moving a window from Activity A to Activity B requires two steps:
- First, move it to All Activities (note that clicking on Activity B in the menu moves the window to All Activities anyway)
- Second, move it to Activity B

I don't know if https://bugs.kde.org/show_bug.cgi?id=382802 is a duplicate of this bug too.

(In reply to Dmitry Vakhnin from comment #0)
> I have 2 activities. When I need to move window from 1 to another, I'm
> pressing right button and choose "Move To Activity". Now behavior is that
> window will move to another activity but it just get status "All
> Activities". Expected behavior is that window will move straightly to
> another activity.

I would not consider this a bug, as a window can belong to more than one activity, which becomes clearer if you use 3 or more actibvities. Maybe you want to vote for this: https://bugs.kde.org/show_bug.cgi?id=271686

(In reply to zeta from comment #2)
> (In reply to Dmitry Vakhnin from comment #0)
> > I have 2 activities. When I need to move window from 1 to another, I'm
> > pressing right button and choose "Move To Activity". Now behavior is that
> > window will move to another activity but it just get status "All
> > Activities". Expected behavior is that window will move straightly to
> > another activity.
> 
> I would not consider this a bug, as a window can belong to more than one
> activity, which becomes clearer if you use 3 or more actibvities. Maybe you
> want to vote for this: https://bugs.kde.org/show_bug.cgi?id=271686

No, I don't need shortcuts. You can see normal behaviour for moving windows between desktops, but between activities I think that's a bug.

*** This bug has been marked as a duplicate of bug 382802 ***