This frequency of English localization issues is unacceptable

[Midareyukki]

5. But is this fine? And does this not cause any problems?

Whether it's fine or not has to go through 2 sides. In order:
1 - The dev team overall
2 - You, the player
And I say "in order" because you aren't given a choice as to what you'll be consuming. It's up to you to give feedback on this. And so far, the feedback they got was that the English Community finds the changes acceptable. There is a positive outlook.

If you're bothered, then you're free to state as much, of course. It's just that it doesn't make it a bad translation in itself. It's at least a special translation.

As for problems? They exist. Creative freedom away from the original author's intent will always cause setbacks, and off the top of my head I can name two:

1 - Nael van Darnus's gender was unknown in Japanese. They never referred to Nael with a gendered part of grammar, since Japan can keep gender vague. English cannot, and they assumed Nael to be male. Come Coils and she's a woman. So the English team had to rush to Koji Fox about this, and he had to make up on the spot a bit of canon to justify the change. That the Nael we see is Eula van Darnus, his sister who took over his position when the real, male Nael died.

2 - Phlegethon, the final boss of Labyrinth of the Ancients. Until then, Titan in JP was called "Tai-tan" (I think?). But then came LotA and the final boss's name was "Titan", but read "Tee-tan" in Japanese. Now, English makes no such distinction, so they renamed him to Acheron, a palette swap of the FF3 boss the LotA boss is based on. All fine there... until Crystal Tower added Acheron mobs. The dev team again had to scramble for a solution. Acheron is a river in Hades, along with others like Lethe and Phlegethon. Thus they renamed the boss into Phlegethon.
And there's even an NPC acknowledging this about Phlegethon.

6. But that's still the sign of a bad translation, right?

...that's where I can't exactly say for certain. I called it a special translation, but I'm hard-pressed to call it a translation at all. It's a localization for sure. But with a lot of creative differences (which are allowed in this one case) that I can't tell if it's a simple case of software localization or just "an added author".

Regardless. You're getting exactly what the others are getting, but with minor tone differences and different mentions. The text may be altered in a scene to better fit this tone shift or to just make the situation clearer or consistent with the rest of the game. For better or for worse. So in all fairness, you don't lose out on much, and it's still Final Fantasy XIV.

There's far worse out there in the market. This is just a quirk of the FF14 team.

[Silverbane]

You're getting exactly what the others are getting, but with minor tone differences and different mentions. The text may be altered in a scene to better fit this tone shift or to just make the situation clearer or consistent with the rest of the game. For better or for worse. So in all fairness, you don't lose out on much, and it's still Final Fantasy XIV.

And frankly I wouldn't even notice the changes if I didn't vastly prefer the Japanese VAs to the English ones. Just personal preference I'm sure, but that's the reason I listen to the Nihongo and read the English.

I know just enough Japanese to notice the changes, but ...
I also know just enough about Japan to accept them as probably appropriate.

[Xirean]

Thank you for breaking a lot of this down.

1 - Nael van Darnus's gender was unknown in Japanese. They never referred to Nael with a gendered part of grammar, since Japan can keep gender vague. English cannot, and they assumed Nael to be male. Come Coils and she's a woman. So the English team had to rush to Koji Fox about this, and he had to make up on the spot a bit of canon to justify the change. That the Nael we see is Eula van Darnus, his sister who took over his position when the real, male Nael died.

This is honestly really stupid imo. English already has a way to make gender vague and that's with neutral pronouns. If they messed that up then I would ask "Why didn't they clarify the gender of the character instead of assuming?" But to realize they made a mistake and create new lore to avoid admitting the mistake is really bizarre to me. I would have apprecated more if they just said "Yeah we messed that up when we first translated/localized it so we'll try to fix it."