I have spent the past hour or so on the Flickr help forum. It contains a lot of questions from people who have had lost photo problems but very few answers.
A few of them were from groups a few years ago who had the same problem as we are having now. It seems Flickr has not fixed them.
They opened a group, some of them new, private and the photos began to disappear from the group.
They remained with the originator and the individual counts for the members even remained the same however, the group count only showed what was on the pool that was shown.
I have submitted an email to flickr help and hope to recieve an answer tomorow or soon as to what may be the problem.
It looks like they are getting more photos to their site than they can handle and things are going out of sync or cannot hold up to the load.
I will keep everyone posted as soon as I find out something from flickr.