Print itunes CD covers - Mosaic leaves blanks

Hello,

I have used this feature for many years. I prefer to use the mosaic theme option, but lately - more often than not - it leaves some blank spaces on the CD cover. If there are not enough different albums to fill the x-number of squares - then why can't it not just duplicate some? It has done that for one album only - see the attachment.

Would be great if the choice of CD covers and their location on the printed item didn't happen all so automatically.

Please apple, it shouldn't be too hard to sort this one!

I am using itunes 12.6.2.20

Many thanks