As Wiking correctly pointed out victory points are scored for destroying/damaging enemy units and capturing flags.
Flags / Objective markers can score between 1 and 250 points each and can all have different values. If you take 15 worth 100 each I could easily draw with 5 worth 250. Thats before I destroy a couple of your 600 point MBTs!
Also included is any costs asociated with having an artillery overload.
Remember too, that if you dont win by more than twice the points its still a draw!
From the GG:
The 2 sets of VP are expressed as a ratio to determine victory. The victory result is then determined as follows
- decisive victory - your ratio of points is 8 times the enemy's or greater
- minor victory - your ratio of points is 2 times but less than 8 times the enemy's score
- draw - whenever either side scores less than 2 times against the other side.
- minor loss - your opponent scored a minor victory over you
- decisive defeat - your opponent scored a decisive victory over you
Please note that partially damaged units count, so if you do 23 points damage on a 100 point AFV, your score 23 for that damage.
So neither a bug nor coincidence - It's how the game has always worked...