album highlight feature not working consistently.

This album has been up for several years with no real problems. Lately when we choose a different photo for the highlight, it fails a good bit of the time. the end result is a bad link on the album highlight photo. We've tried a lot of different photo's and can't find any pattern as to why some work and others don't. It seems to be much worse on some albums with one that we can't find any photo that will highlight.

Gallery version = 2.2.5 core 1.2.0.7
PHP version = 5.2.17 cgi
Webserver = Apache/2
Database = mysqlt 5.5.32-log, lock.system=flock
Toolkits = ArchiveUpload, Exif, Getid3, ImageMagick, LinkItemToolkit, NetPBM, SquareThumb, Thumbnail, Gd
Acceleration = none, none
Operating system = Linux boscustweb1602.eigbox.net 3.2.44 #1 SMP Tue May 14 15:31:28 EDT 2013 x86_64
Default theme = matrix
gettext = enabled
Locale = en_US
Browser = Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/31.0.1650.63 Chrome/31.0.1650.63 Safari/537.36
Rows in GalleryAccessMap table = 48
Rows in GalleryAccessSubscriberMap table = 174
Rows in GalleryUser table = 3
Rows in GalleryItem table = 172
Rows in GalleryAlbumItem table = 13
Rows in GalleryCacheMap table = 0