when I lock the screen it turns back on immediately?

when i click the sleep wake button on my xr the screen turns black ( it goes to sleep) but than immediately turns back on and off by itself. its draining my phones battery because it wont keep the screen off. ive checked the settings to see if the timer settings need to be changed or the raise to wake is off or on but none of this has helped. i have tried new screen, battery and charge port as well as front facing sensor. it continues to do it