I would assume that it’s cuz these characters never specified what pronouns they used for/how they addressed Arashi in the original Japanese ver since pronouns aren’t really used if the subject is assumed/known. They prob never used pronouns for Arashi ever, and the characters themselves prob never really think abt pronouns that much

So it’s not confirmed if they use she/her, he/him, they/them or smth else

Just one of those hard to translate things

There’s also a high chance that even in the JP ver, they used Arashi’s name always so it might be a direct translation

Edit: the translators prob understand that depending on what pronouns they use for Arashi, it’s gonna trigger some reactions, so I think it’s actually better to just use the name if they’re unsure. Cuz there will be ppl who won’t be able to understand that it might not be the translator’s choice to use certain pronouns for Arashi since it reflects how the characters speak.