The 58% glitch is a known one. It's been a problem for everyone in my family since the game resurrected in November. Windows 11, Mac, iPad...happens on all systems. Inconsistent, but happens a lot more often if attempting to adventure with a mixed group of new and old characters. One of my kids has all but given up playing because of it.
@Dathmaul_Crinklegadget If you are still on "Trouble Afoot", keep walking every inch of the lagoon. It's not completed by reporting back to Alexander. I went back and forth three times, then finally completed it when I looped behind a rock.
SFTDP, but unless the previous glitch is fixed, after completing "Trouble Afoot", the entrance to the Lagoon permanently disappears. (Might happen after leaving the Lagoon at all, but never tested that...maybe you could let us know if you can get back in if you still haven't finished "Trouble Afoot"?)
I've had the follow-on quest "Eliminate the Fog" for a few weeks, to no avail. Stuck because I can't get back in, and I'm one of many.
Idea for @Hermie_Voncase: If the trigger for getting the entrance to the Lagoon back (and getting it back permanently) could be tied to asking Alexander about the quest, rather than upon receiving the quest, then everyone who is stuck would have an easy resolution avenue.