How old is this dog? If she is a young dog (and by young I mean under 2, believe it or not) it could a lapse in potty manners, due to a late 'puppy stage' in mental development.
Next I will suggest a simple exam to rule out any bladder or UTI troubles. When house training lapses in a once obedient dog, it can often be traced to pain.
The larger the dog, the later these stages can occur. My BC mix went through a 'mental lapse' at about 19 months, and it lasted about 4 months...then as quickly as it appeared, it disappeared. Her's wasn't potty related, but more of an all of a sudden, "I'm afraid of everything" type stage.
To help her get over this behavior (development related or not) I would advise either cleaning that bed with an enzyme cleaner...IF the stuffing doesn't allow you to, you may need to get a whole new bed. If you don't have an actual private area in which Bea can retreat to, like a kennel, I strongly suggest you get one; give her some space in which she can relax without kids, parents, or cats. Put her new bed in the kennel, or room that you choose, however, a room will be harder to moniter, due to open access to the cats.
Try to limit access to her 'bed', and especially only give her access to it when you know she has done her business outdoors. Then give her a 'reward' by letting her go to her lovely den complete with treats, and soft cozy bed. This crate training can also be beneficial in that your dog has a place to go to when she is fatigued from a long day...because it will be a quiet place where she will learn that no one disturbs her; and the biggest benefit is that she won't\\or shouldn't develop the 'need' to mark that territory because the access is limited to only her. My dogs love their kennels, and they are only usually in them for a few hours a day; they crash out after they eat their treats. However, because I know they are comfortable in them, I also know that if there comes a time when they have to be kenneled (due to illness, or injury, surgery, etc) I know they won't be 'illprepared'...
If crate training won't be an option for you, then when you take her out to go potty, take up her bed. Don't set it back down until she goes potty outdoors; whether that means her bed stays up all day or not. It doesn't matter how it started, This behavior can become a 'convenience' behavior for her, if she is allowed to go inside and urinate on the bed even after being outdoors for that purpose. So simply keep that temptation "up" until she catches on, that her bed is not an acceptable aversion to peeing outdoors.
You could also gate her off in a room with easy to clean floors for those times when she doesn't potty outside; keep her in that gated off area for a good half hour-hour (depending on her age) before taking her back outdoors for another try; in this case, pottying will be her key to being 'free' once more in the house.