Caveira’s unique skill is Silent Step, which is primarily used to allow her to move around while making far less noise than other characters. Silent Step can be used for up to ten seconds, and then requires a few seconds to recharge. When activating the ability, Caveira’s stance changes slightly to reflect her stealthier movement, but it turns out that this is causing a major perspective issue.
As pointed by YouTuber Get_Flanked, if Caveria is already crouching when she activates the ability, she shrinks down even further. If she’s hiding behind a waist-height object, she becomes almost entirely invisible, but her perspective doesn’t change. That means that while she’s completely hidden behind a box or a desk to an observer, from Caveira’s perspective she’s still poking her head – and crucially her gun – out from behind cover.