project server training london - When allocating Resources to a project, Project isn't showing th

I'm attempting to add resources to a mulitple task within one of four projects that shares a Resource Pool.

I'm having difficulty because the Assign Resources screen isn't retaining the % I'm entering. Project and the Gantt Chart view shows I've assigned the resource, but not the % allocated.

Also, in the Gantt Chart view, where the Resource Name Column usually displays D Smith [100%], A Jones [50%], but the [] (brackets) displaying allocations aren't carrying through.

This is only happening on one of the four projects.

Can anyone help please?

Many thanks, Rob