Deathfire Touch/Liandry's glitch

Want to report a bug about deathfire touch mastery and Liandry's proc's resetting each other for 2 to as much as 8 full seconds after the last hit has been made. It appears that when timed correctly, these 2 skills are resetting each other. (just these 2 skills seem to be actually refreshing each other) First noticed it on brand, but can replicate it on cassiopeia. Appears that maybe the timer is getting bugged on champs with D.O.T. passives.