It may be specific to your particular keyboard. One of the things to look for in a gaming keyboard is "n-key rollover." The keyboard may be limited in how many simultaneous keypresses it can track. A keyboard with true n-key rollover (like my CVT Avant Prime) can keep track of every individual key, up to all 100+. Usually, a 4-key or higher rollover works well enough, but a 3-key rollover is not enough for some games.
i7-8700K, H100i v2, RoG Strix Z370-G Gaming, 16 GiB, RX Vega64, 960Pro SSD, 5TB HDD, Define Mini-C, SS-660XP2, C32HG70, RK-9000BR, MX518