DVE test paterns. Advice needed!

I asked this question in a post in the Arcam forum but got no response so thought I my be better off putting it here.

I've just been playing about with the PAL Digital Video Essentials disc on both my Denon 2900 and Arcam DV27A and found some differences in a test pattern but don't know what it means so hope some of you can help!

When displaying the SMPTE test pattern in the picture resolution section of the disc, the 4 squares in the corners of the pattern were badly flickering (along with one near the middle). On the next test pattern (Multiburst Vertical) the 2 bars marked 'Full' were doing the same, almost like a strobe light! This was using the DV27A with progressive scan outputs into a Sim2 Domino20.

When I tried the same pattern using prog. scan from the Denon there was no flicker at all in either test pattern.

I then tried interlaced out through the component out on the DV27A and although the flicker had gone there appeared to be a darkened area in the middle of each box/bar that wasn't there with the Denon.

As I said, I've got no idea what this means so if anyone could explain it to me I'd appreciate it!