Yeah I also thought that was odd, but not understanding Japanese I'm not clear on the cause of her sudden fear in battle. Maybe related to something in the Golda/Liorga fight? Either way, she didn't look so weak after her summoned gang of shadow demons started eating faces!
Also, just noticed that takaratomychannel on YouTube uploaded this new promo last week, including an...interesting interview with the animation director. Seems odd timing to have this 'announcement' as the show has already been airing in Japan for three months now, but it's in English so I guess this is their way of officially reaching out to the Western audience.
Yeah she wsn't weak when she got passed her fear and started actually fighting, which makes the sudden fear all the more jarring. Those face eating shadows were pretty darn cool!
I think I saw that interview before, but without subtitles.