I have an IIS website that serves content via Apache (ProxyPass and ProxyPassReverse - the reason for this weird configuration is historical). The Apache is behind other company proxy servers. The site has static files and one virtual directory for the WebAPI part that serves JSON.
Users are sometimes getting wrong content - for example, visiting the home page returns an image linked on the home page, or some other html page on the site, or some JSON (from the WebAPI). The home page has caching turned off.
This usually happens when the server is under stress (database freezes up), but happens otherwise as well (but rarely) but not with enough frequency or consistency that we can debug.
IIS: version 6.1
Apache: version 2.2.13
What could be causing this intermittent issue, or is there a good way to figure out what's going on?