There are beats dropped in both the guitar and vocal - the vocal comes in too early and sometimes the guitar seems to play an extra beat. What might be happening is that your timing issue is creeping into both the tracks and the singing tries to follow the guitar but actually moves the 'error' the wrong way.
I've a suggestion though, The problem I think is coming from that rhythm you are strumming. Have you tried it just as a straight 4/4 on the beat pattern to get the chord changes in the right place. As it is, you sometimes change the chord on different beats in the bar, which then makes it sound like a beat has got lost, when it was just a bit early on the change. The other thing is those stops. They're not really tempo changes, they're pauses, but then they come back in somewhat randomly - which is fine, if the vocal can follow them. This will bugger up the click, and while you can break the click, and resume - that's very hard to learn to do. Maybe for the moment, scrap the pauses, and try recording the song rigidly to the click or metronome. The triplet feel to the 4/4 is quite a hard thing to play if you are not used to this kind of thing. Maybe you're galloping, not even running before the walk is mastered?
With both the voice AND the guitar wandering all over the place, it's hard to decide which is right. Clearly they don't match, but I think on balance it's fixable, but you need to master playing that rhythm consistently and reliably so the voice has something to lock into. In some bars, the guitar plays too many downbeats so the vocals guess which one is the downbeat, and discover 2 beats later, it was wrong. Practice the chord changes in the 4/4 - one strum per beat, or at 1/8th notes with two strums per beat till you feel comfy. The rhythm is very hard to repeat over and over again. Keep going and report back.