This just happened last night to a squad mate of mine during the Yavin conflict. His level VIII Imperial base was attacked by 13 rebel troopers with no support. The battle lasted 62 seconds and ended with 2% damage. Yet when the final screen came up, it showed he had lost 100%.
The only possible benefit of the doubt I could see here is if the attack occurred after someone had lost connection to the main server or something along that line. But even if he had been hit by a full up level X force, they would have had a hard time completely flattening his base in the 58 seconds that remained. This one in my opinion is very suspect.
I made a screen grab video of the attack and results and can make that available to whoever wants it.Video of suspect attack