Keys, I have been following this thread and had nothing to contribute, but at your request I took another look at it.
Like Tacit I am unfamiliar with the product you are using and the guess about it being a cache problem is as good as anything I can come up with. When I was earning my bread and butter as a software design engineer I ocassionally saw similar problems caused by failure to do garbage collection in the code — essentially failure to flush a memory cache internal to an application — or an incorrect API (Application Program Interface) call possibly to to the webkit. But without access to the application source code and potentially a lot of debugging time that will have to remain as speculation or to be more accurate a wild guess.
