Sorry if my post is hard to follow but Its hard to put this mess in a way that can be understood also I was in a hurry.
That's very sweet your D was so excited to see you grin I love that age, when they're so excited.
Me to, she normally is happy to see me but today was off the charts. wild horses weren't going to keep her away

The sad thing is that she used to be excited to see her mom when I brought her back to her but its getting less and less lately.
My ex would also rant and then pivot abruptly, as though nothing happened. This went on during our marriage, and also after when we shared custody.
Its very troubling because you don't know what to expect next
I talked to my therapist about the different times it would happen. Her perspective was that it was psychosis, but when I tried to read more and understand exactly what psychosis was, it was hard to figure out how it was different than dysphoria or dissasociation or delusional thinking.
One thing she does is say she told me something when she didn't. I really believe in her mind she believes she told me because she was thinking it at the time or even later on, because she thought it that makes it fact. usually she only does this with one thing but this time it was a stream of things one after another. It was like she had a 2 hr conversation with me about all this stuff and then was reminding me of what we talked about, unfortunately I wasn't present for that conversation. Scary stuff
ps. glad to hear it wasn't herpes! That must be a comfort to confirm what you had suspected.
Even with the proof my ex still refuses to believe that its a canker sore.
Eco does she act like this with the other x. Does she just have kind of a standard dialog that she uses with both of you.
My ex has 3 kids with 3 different dads, Dad #1 she was married to for less then a yr and it ended with a her pulling a knife on him. they went to court and she lost her daughter briefly because of the assault. somehow she got custody back and they didn't get along for a while. When I came along she was civil with him and somewhat friendly, he is allowed in her house to pick his daughter up.
Dad #2 was a one night stand supposedly and they had a brief feud and he didn't see his daughter for her first year. now they get along just fine, when I was with my ex we would go over to his house and eat dinner on some holidays and I eventually got him a job where I worked. I got a lot of the truth about my exs past from him, he never went to court and got legitimized as the father so he doesn't have any rights and I think he is afraid to.
I am treated like the devil compared to the other two dads, The only thing that bothers me about that is how its going to effect my daughter. She sees her sisters dads able to come into her moms house and they are allowed to bring stuff home from their dads like stuffed animals, pictures and such.
Have you thought of getting a cheap tracphone you could use just for her, and throw it in a drawer and only look at it once a day. Or only communicate via email so you don't get her b.s. all day.
Luckily I don't deal with a lot of contact from my ex since I quit feeding the drama monster. I cut things short and to the facts and I don't respond to most of the nonsense. the only time I engage is if she tries to interfere with my daughters time with me.