trouble with map and reference map inversion (4.4.1)

[Lionel Bargeot]

Hi,

I've just installed mapserver 4.4.1. I have a problem with reference map
and map inversion.
My script worked fine with the previous version of php-mapscript. But
since I upgraded, I have a very strange trouble.
I use basic pan and zoom functions.
I can show you basic and right result here :
http://www.igcs-stb.org/pdf/mapserv_without_trouble.png

I repeat my operations (zoom -, zoom +, pan, ...) and sudenly, I obtain
a very strange page :
http://www.igcs-stb.org/pdf/mapserv_with_trouble.png
My reference map is wrong, and I otbtain my previous map instead.

or the inverse problem :
http://www.igcs-stb.org/pdf/mapserv_with_problem2.png
My map is wrong and I obtain reference map instead

At the begining, I believe problem was coming from my client (image in
cache), But it's not the reason (same results with no cache).

I verified the name of the file in page source code and opened it
manually. And then, I see something very strange :
In source code of the page with the reference instead the right map on
my screen, the name of the file is 110751814976776.png. And if I open it
manually in my tmp directory with gimp or another software, I see the
right file (the right map).
So, the image I see on my screen as described in source code isn't the
right file it points to, on my server.

I note if I reload the page, all comes back ok.
I note that frequency of the trouble increases with cpu load.

So my questions are :
Could it be a non mapserver problem ? (perhaps it's not the approriate ML)
Has someone else encountered this problem with new mapserver version ?

Thanks in advance,

Lionel