I've been having Reserving Server issues ever since the FFXV event dropped.

I assume it's the influx of players doing duties that's overloading the servers. But, I've been having Reserving Server when trying to do any Undersized Party dungeons (Halatali (Hard), Haukke (Hard), Pharos Sirius, Tam-Tara, Toto-Rak etc... Basically dungeons you need to do for Zodiac books)

Heck, today I even had it when trying to enter Eureka Anemos (I then joined an instance with like 100 players in, go figure)

That said, I've never been stuck due to this, more just having to wait an extra minute or so before getting in...

Perhaps this is something to do with the World Visit system? Like, maybe when people are using World Visit, it happens to use the same server space as trying to enter a duty and thus it gets clogged up with people hopping worlds and so people trying to enter duties get shafted?