* It's possible that something happened between Jill and the managers/co-founders that the rest of the group is unaware of, and she felt that it was best that she leave. * It's possible that her health issue flared up again and she decided to leave. She may have been quite appreciative of what the group in her previous absence but didn't want to/couldn't go through having you all pick the slack - either her choice or management's. And she didn't know how to gracefully exit, so she abruptly left. * Maybe she got ill again and the goodwill "debt" she incurred had nothing to with it - she just needed to leave again to tend to her health - and was unfortunately, not gracious in her departure. * Maybe she was forced out and has been prohibited from saying anything - or simply chose not to.