http://prntscr.com/5kqc8p
http://prntscr.com/5kqe1i

wth.is.this.we.conq.the.op.and.there.wasnt.any.3rd.party..so.now.what

we.lost.5.valuable.ticks.and.will.cost.lot.in.war

pls.fix.this.bug

I think what has happened is:
You and your friend attacked the same OP with same ETA. And someone else also attacked it with same ETA.
The as per the rule all attacking forces will fight together against the defending ones and then the two largest forces will fight against each other for the control of object they attacked. And all the other forces will return back to origin.
So your friend who sent more units than you and the 3rd party who also sent more units than you kept fighting and your forces turned back.

If you can tell us what actually happened, then it would be more helpful.