Still not fixed in 6.4.19.3 _ Regards.

we changed the copper pour and 3d view since v6.4.17, it is normal for supporting multiple board outlines, such as panelize manually.

@UserSupport, Thank-you for your reply but I'm failing to understand what any of that has to do with the original problem. _ Perhaps I didn't make it absolutely clear what the problem is, let me try again. _ In version 6.4.14 a SINGLE board with a hole defined by the outline, on the outline layer...  _ ...would render a board WITH a hole.....which is what you'd expect, and want.  _ However, since version 6.4.17, the same project, with the same board, with the same hole, now doesn't produce a hole...  _ Regards.

Yes , it is for solve the panelize copper pour doesn't apper issue, we change the copper pour and 3D view, not cutout the board in 3D anymore. 

@UserSupport, Thank-you again for your reply. Are you seriously saying that in order to fix a completely unrelated [to me] issue, you deliberately broke the 3D view? _ That is just rediculous. _ Regards.

@UserSupport The outline you posted as example doesn't really make any sense. It is really bad design with lots of wonky and overlapping lines. A correct outline for a single board should also work fine on a panel since none of the outlines would intersect when panelized. The rule usually is that to determine if a point on the pcb is solid or not, you draw a line from the point to infinity (in whatever direction) and count how often you cross an outline. If the number is odd, the point is solid. If it's even, it is a cutout. I'd also appreciate a better fix that actually leaves cutouts intact.

Just for the record...neither 6.4.19.4 nor 6.4.19.5 fix the issue. _ Regards.

@mrtom528 we will not deal with this issue, because if only impact the preview not the design. and current logic can solve the copper pour issue. the gerber doesn't different than before.