An acquaintance who I knew in highschool has since transitioned. Before publicly identifying as a woman she had a relatively neutral British accent with a some with a slight hint of Scottish. Since transitioning she has a full on lilting highland accent. Which i found odd. I have a similar accent to her original accent and decided to try doing a girl voice to see what it would sound like. And i too developed a strong Highland accent. Why? I was specifically trying not to.
Possibly you’re over-enunciating? I’m from the south of England originally and usually talk with a fairly international blend, but when I started voice training my accent turned very plummy.
You could try impersonating someone in particular: repeat lines from a move or game, even. Or try a totally different accent. Valley girl is fun :)
Yeah I can sort of do Edinburgh, Belfast, Larne or other regional accents, but I definitely don’t sound like that normally.
I found that I could go back to my normal accent once I got used to doing girl voice. It’s probably something to do with habit and muscle memory, but who knows.