nRelate was showing 6 thumbnails, then suddenly only one per post?

Hi there,

The website I am working on has nRelate installed and activated and it was working great! I had it set up to show 6 thumbnails which it was doing perfectly (all test posts with lorem ipsum at this stage).
Then suddenly today (because yesterday it was still fine), only one thumbnail was showing, and particularly of one post (sample petite cousine post ). under the actual sample petite cousine post post there was no thumbnail at all.

It seems as all other posts or perhaps categories are excluded from the related plugin, but in the settings this is all set correctly, I have nothing ticked here:

Select the categories you want to exclude from ALL nrelate products. If a post is in multiple categories, and one of those categories is excluded, it will not show up.
EXAMPLE: You published a Post in categories “A” and “B”, and you only exclude category “B”, the post will not show up, even though category “A” is to be included. Since the post is in an excluded category it will not show up.
Categories:
• Family
• Fashion
• Lifestyle
• Petite Cousine
• Uncategorized
• Wine/Food

I can’t see what else would have caused this…
I looked in the post to see if there was an nrelate tick box or other settings that may had accidentally been ticked/unticked, but I can’t see any.
I deactivated a couple of plugins (that I installed last week) to see if that was interfering but didn’t seem to make a difference. I changed the date on a few posts to May and that didn’t make a difference either.
Then a few hours later one more thumbnail has started to show up and currently it is showing 3 to 4 thumbnails per post, but still not the full 6, even though there are enough sample posts to fill up the 6 thumbnails. I wonder if it’s because I changed the post date to May??

I have not changed any settings since yesterday when it was working perfectly and I’ve set “How relevant do you want the results to be?” to low (recommended)
What could be the problem please?

http://wordpress.org/extend/plugins/nrelate-related-content/