Is the sub a bug?

[Dennis Pang]

I'm confused because some of matches I played lately when I made a sub, either my team or the other team scored right after the sub. It happened several times in the past few days.

Coincidence? don't think so...

[Cat Harrison]

when you make a sub, of course it will make an impact on the match. isn't that the point?
I find that for me I like to only make one sub at the half, and maybe wait til late in the game for any others.