I actually have come across it full blown, but also was accused of it.
I think the wisdom of Solomon is sometimes needed to know what is what with these things and there can be overlaps.
The accusation I faced was a school trying to cover up bullying and stop assessment for an ECP (as it then was) as they didn't want to be seen as having gone down the wrong path in the first place, whipped up by an inept SS department in the spotlight for it's failings.
I'd sought no medical help as Ds was very young and fine at home. A bit sensitive maybe, and incapable of lying to save himself. A tendency to go onto tiptoes, and carry his arms oddly and flap his hands. (all obvious pointers now, but not then)
But issues arose in school from day 1. Long story short - apparently being fine at home meant he could only be his 'true self' at school, so home was the issue.
Reality was school was a confusing environment that magnified difference. Home was a straightforward environment that didn't.
School told SS injuries in school were him actively lying he was being bullied to cover up that they were really from home, and to get others into trouble. Parents of kids involved, were keen to agree.
In the middle of it I asked GOSH for help, unaware the worst thing a parent (especially a physically disabled one) accused of MBP/Fil can do is ask for a medical opinion to decide if there is or isn't a problem!
I naively thought it was the obvious thing to do was ask medical professionals, rather than educational or child protection ones.
The first thing GOSH said, was Ds "didn't have sufficient theory of mind to try to get others into trouble."
Eventually we ended up with ECP, diagnosis and home ed. He made friends, did well educationally and went to university and into work. He is however still developing, late in life and will never accept help or financial support from outside of home.
We were very lucky that GOSH robustly diagnosed, and supported, but we went through hell and the damage to the whole family is permanent, so I'm cautious, but I've also seen a real case of it full blown and the damage there is equal.
....................
However the 'full blown' involved the active tampering with blood and urine specimens and behaviors that caused active symptoms of ill health, and some physical damage, though I think a side effect rather than intended.
It started with being had a go at for the child's low attendance, obesity, and aggression at school. There is no question that there is violence at home, and the child has been both hit for taking part, and also in other situations encouraged to 'get in there' and they are allowed and encouraged to gorge on fast food, which the others are not. They supposedly have to be catheterized every time to pee, and have been rushed to hospital repeatedly around this, but go normally in other peoples homes when Mum isn't about.
I think it became a mixture of parental defense, then parental attention, then financial reward. The child is now out of school and his mother is clear he will never work and be benefit dependent, so education is a temporary box tick exercise only.
Some of his difficulties have underlying realities, but the level to which they've been encouraged and manipulated have left him with a difficult future and he believes he is disabled, can do little and wont ever work.
Every time another YA sibling is in trouble, or SS get involved over a younger one, the other one's conditions turn into emergencies.