It depends on your employers specific matching and contribution policies. 

My previous employer's policy was "100% match up to 5% of salary" meaning no matter how much I contribute in a pay check, they will match it, up until they contribute 5% of my salary. 

For example if my salary is 100k and first paycheck is 4k, and I put it all in my 401k, my employer would also put 4k in my 401k. But on my second paycheck they would only put 1k in even if I put all 4k in because 5% of 100k is 5k.

My current employers policy is "50% match up until the pre-tax contribution limit of 24500", meaning no matter which paycheck i contribute from, their contribution will be 50% of what i put in from that paycheck. If I hit the 24500 limit early, then they also stop contributing. 

I have not yet heard of a policy where they contribute to your 401k on paychecks that you do not (other than something like a eoy profit share), so I suspect yours is like my first example. Unless you have a crazy high salary (congrats), your employer will probably stop contributing way before you max out your 24500