avoid data pack reload upon relog

I set up this data pack for a challenge I'm doing where there's a 30 minute timer, and after it hit 30 minutes, I'd permit myself to obtain an advancement.
And for a while, it worked exactly the way I wanted it to.
However, somewhere along the way, something broke.
One of the nice things I liked is that if I logged out and came back, it wouldn't reload and it would simply pick up from where it left off, so I could go into a creative world midway through and then come back a little later without it resetting.
But now it doesn't do that. I suspect that now, relogging triggers the load function every time now.
Is there a way for me to fix it?