Probably a few factors, its easier to be confident and take more risky plays in scrims where there is nothing to lose, alot of teams in scrims are willing to take risk and push to take areas but in officials they play more safe because more on the line. You probably only heard about Team X doing bad in scrims, not when they did good/average. Scrims are different, people aren't juiced up on caffeine or warming up for hours so there can be alot different, also teams work to practise certain aspects of their game, they dont practise to win.
For example RRQ could seek to test their skill against a strong apac opponent to have good vod review footage/see what level they are at while the other team could be thinking lets practise our default or communication or whatever. Doesn't mean that anyone is not treating the scrim seriously but obviously there would be different in result compared to official.
Obviously this is a long post for a vlr random thread but hopefully you can understand better
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