I also had/have no specific sort order. For now, this is resolved, it has been working flawlessly after physically removing and rebuilding the files.
I can sense quite a bit of - understandable - frustration @dj_paige - I should have described the issue more in depth, so it didn’t read like “hey, I installed LR yesterday and I have a problem” - I was in a rush to get a solution while being in the next shoot. And yes, I HAVE inadvertedly pressed keyboard shortcuts before, and since LR is the only software I learned using without those, it is very well possible I just don’t know enough to count as a “safe” person to ask questions here.
Thanks for taking the time @dj_paige & @JohanElzenga