>>(a) Something it triggering an unexpected recompilation (this thread)
>
>Here is the result.
>
>The problem was caused by the robot. That one was created .html files into the Static directory. The problem was not there. The problem was that the Default.aspx page was including INCLUDE command to insert some of those HTML pages into specific areas of that page. I changed that into Literal and have the .DLL to replace that instead.

Looks like you nailed it (I wonder whether using Response.WriteFile() would also avoid the issue.....)