For some reason, sometimes when I'm AC strigi automatically suspends itself. I right-click the tray icon and uncheck suspend and some time later it might suspend itself again.

There doesn't appear to be any pattern to when it decides to do this. Any ideas?

Another problem is that if I boot off battery, sometimes strigi doesn't auto-suspend. But it has no problem when I'm already in KDE on AC and then unplug and run off battery--it auto-suspends just fine.

This will happen I believe if your computer is under load, ie. intensive disk access, as well I believe.

It happens even when the computer is not under load, or if it is, just for a very short period. But also, strigi is not even indexing when this happens. I thought it would suspend only when under load and in the process of indexing.

I guess this would also occur if Strigi has finished. That is the only thing that would explain it.

Just to add my 2 cents, to me this happens when the screen saver kicks in. Which is funny, because my screen saver is a blank screen. And this happens while I am on AC.

I wouldn't expect that... I'd expect Strigi to pick up speed indexing when the screensaver is running assuming load is low. You may wish to file a bug report at bugs.kde.org.