What the Filament?

So.... my printer did the strangest thing. I don't know what happened. Got new software, via new computer and reinstall. I had to put in my old custom start and end code, as that was apparently left out. I don't know what the thought was on default start and ends. Leaving the extruder right where it is when it ends, oozing and melting nearby parts of the print. Anyways. I've had a few good prints. But out of nowhere, at the end of a print it decides to raise the bed, not moving the extruder to home, both of which were strange. It murdered my 3 hours of printing, too. I've spent plenty of time printing and this is something that makes absolutely no sense. An anomaly. So I'm here.. asking what happened.