Issue with block update mechanics

hey all

I'm making a procedure for a projectile in my mod that basically checks if the block at xyz is air on a  tick update and if it is replaces it with my custom invisible light block. I have this light block set to despawn within five ticks, which works great 99% of the time, but sometimes the blocks created by this procedure do not delete. I've changed all sorts of tick settings and nothing has made a difference. I am assuming this issue has something to do with the block not properly updating or ticking, but I'm not sure. If anyone has done something like this and fixed this problem I would love your help. Thanks in advance! :)