This is really annoying

I have been noticing that the radar in the bottom left of the screen is EXTREMELY buggy. It will only register enemies who are within a few steps of you, and it takes about 10 seconds for the radar to detect enemies. What is the point in a radar if your dead before you know if anyone was near you?

Read this

If they’re walking even a bit slower than full walk speed they won’t show up on motion. May also occur if you or your opponent is laggy.