while I were doing this gather tutorial, I asked my friend to remove BE so that I wouldn't get kicked for using fraps. however, I noticed demos worked on it. so I thought I'd try that later, so now today I tried this, and I found out that if the server does not use BE, the demos works perfectly, if BE is activated, demos get laggy and also fails with the access violation and server redirecting.
Below I got 4 screenshots of the BE error, and the first demo is with BE activated (autodemo2.sdm)
the 2nd demo is without BE activated(autodemo65.sdm)
EDIT: Would be interesting to know how long it was between soldat 1.5 and BEs update.