yitayningwut
You’re right, my mistake, it is a machlokes rishonim.
(btw the sugya in shabbos 25: seems to be going that ksus lailah means night time, like the Rambam (at least the way rashi is mefaresh that sugya, don’t know if there might be an alternative pshat))
About the gemara in Shabbos 25: – first of all, that whole story about Rav Yehudahs minhag is not so clear to me. How is he like a Malach Hashem? I would think that it is because he is wearing the white sdinin (white is a color associated with malachim in other places). So what does it have to do with erev shabbos?
Only on erev shabbos he would wear the white sdinin? If so, why?
Maybe it had to do with the rchitzah, perhaps in those days they wouldn’t bathe very often, so when he did the rechitzah on erev shabbos, he became like a malach hashem.
Anyway, i think the simple answer to your question is, he would remove the sdinin that had the kilaim before Shabbos. It does not say in the gemara that he would leave them on, so it could be that he took them off.
Another possibility, that might need to be explored a little more, is that the gemara in Brachos deals with someone who put on the beged bi’issur. Whereas here, the levishah of the beged was biheter.
(it would be a chiddush to say that this should make a difference later on, after the beged is already on, but i still think that it may be possible to draw such a distinction. Since the original levishah was a ‘kum vi’eseh’ issur, that makes the whole levishah, one long kum vieseh levishah of issur. In other words, the maaseh levishah stretches out from when he put it on, until he takes it off.)