Lena and Holly did spend time nights with Ivy, lmcluding some girl-girl secenes (shower, Ivy's house), but generally Lena protected or engaged with Hooolly directly. I guess her corruption has more to do with Ivy's off-camera influence than choices made? I do recall Holly went out with Ivy once but Lena wasn't aware/invited. I guess that was it? Makes sense 'be like Lena = out of shell, but hanging with Ivy means corruption? In any case, it's a real continuity issue where in one scene Holly is the most content and loved she has ever felt, and in the next she is chugging on cocks.There is an error in the code that ffive could probably explain better that might be the cause.
But how much did you protect Holly from Ivy? Because this sounds like something that's still possible if Holly is heavily influenced by Ivy, regardless of Lena's relationship to either girl.