The code that causes it is here: http://hpaste.org/fastcgi/hpaste.fcgi/view?id=5731#a5731 This is the strangest thing. Occasionally, using nothing but gets and puts and frees on a non-full Cache will result in this: Cache { store = fromList [("(\"icons/addBookmark.png\",False)",TextureObject {textureID = 4}) ,("(\"icons/addCircle.png\",False)",TextureObject {textureID = 1}) ,("(\"icons/addContent.png\",False)",TextureObject {textureID = 2}) ,("(\"icons/addElsewhereLink.png\",False)",TextureObject {textureID = 3})] , times = fromList [(61314,"(\"<span font_desc='sans 8'>294.0</span>\",AlignLeft,Nothing,WrapWholeWords,False,0.0,0.0)") ,(61316,"(\"icons/addBookmark.png\",False)"),(61318,"(\"icons/addCircle.png\",False)") ,(61320,"(\"icons/addContent.png\",False)"),(61322,"(\"icons/addElsewhereLink.png\",False)")] , now = 61323 , maxsize = 1024768000 , size = 4 , decimation = 0 } Sometimes the problem is self-correcting. Sometimes it is most certainly not. But I don't understand how my code can possibly allow for this.