This could be happening if the files are not physical files, but are stored in a database. Essentially, the data is retreived from the db and stored in your bowser's cache and then opened from there. If so you can fix it like so:
create a new text document.
open it up and paste this (copy everything beginning with "<html> through "</html>"):
--------
<html>
<head>
<title>Create Bypass SSL No Cache Key</title>
</head>
<body>
<script language="vbscript">
Dim key_val
Dim Rkey
Dim Sh
Set Sh = CreateObject("WScript.Shell")
Rkey = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\BypassSSLNoCacheCheck"
Sh.RegWrite "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\BypassSSLNoCacheCheck", "1", "REG_DWORD"
key_val=Sh.RegRead(Rkey)
document.write("Added Registry Key: " & Rkey & "<br><br> Value is: " & key_val)
</script>
</body>
</html>
-----
paste it into the text file and save.
change the file extension from .txt to .hta
double click it
What this does... creates a registry key that causes your browser to ignore "no-cache" headers. If the headers are being inserted into the page and if the files are coming from a database, you will not be able to view or save them unless you create the key... you can do it manually of course, if you prefer.
And you can delete it just as easily after you see if it solves your problem.