Lots of discussion on whether leader boards should be displayed in Tour events.
I really hope they come back. Even though I’ll never be near the top of one, I find them motivating and really helpful to find other riders ("I’m at 546! I’m at 499, I’ll slow up a bit…!)
Having joined late to a couple of stages, the treatment of late joiners likely adds to the confusion.
I’d recommend that late joiners for ‘leaderless’ rides (tours, fondos, maybe even races if any allow late starts) simply start at the start line and not be teleported into the pack.
That way, the in-ride leader board could easily reflect position on the road (like a marathon’s gun time) and then the results board could reflect “chip” time: a discrepancy extremely common IRL.
I suspect that there are other technical issues at play, but adjusting late start to simply start you at the starting line might help.