Hasn't Angelica talked around the girls before, just not Haruka? Or is she still just too shy because there's also guys there?
She had "talked" (communicated by gestures basically) to them and others before:
Ch.69 pg.8-9 Actually spoken for the very first time to thank him (after that, it's back to talking by gestures)
Ch.124 pg.9 when she went with the girls to get them to Lv100
Ch.136 pg.6 "girl's sleepover meeting" with the princess
Ch.155 pg.11 when Haruka ordered her to go rescue Zero's sister and also when Zero told her to wait, she responded
Ch.158 pg.7-8 when she met the male classmates after they wrecked the Merchant Nation's port and 'talked by gestures' to them that she's to rescue Zero's sister on Haruka's orders; pg.11 when she slipped and hid behind some crates and made her "Nyaa..." cat sound to distract the enemy patrol kek; pg.15 when she "told" Zero's sister that she's there to save her out of the place
Ch.159 pg.14 not really a talk but yeah