Wendy Williams and those closest to her are baffled at why she’s being kept in her assisted living facility’s memory care unit, and TMZ has learned others in that building are wondering the very same thing.

We spoke to people very familiar with the NYC facility where Wendy is living … and they say residents on the 5th floor, where Wendy stays, are mostly in their 80s and up with severe cases of dementia or cognitive impairments.

That account matches Wendy’s own description of her surroundings, which she shared in our new documentary, ‘Saving Wendy.’

“TMZ Presents: Saving Wendy” — streaming now on Tubi — explores her guardianship, and in it, Wendy tells us she’s only been outside in fresh air twice in 30 days … both times for dentist appointments.

While they don’t know any specifics about Wendy’s case, our sources find it odd the guardian hasn’t gotten her moved if she’s unhappy living there, or feels she is much higher functioning than the other memory care residents.

We’re told the facility is not a nursing home and there are no doctors or physicians on staff, so residents need a family member or someone from the facility to accompany them to a doctor’s office or have the doctor come to them.

That’s a major problem for Wendy, as she told us she’s rarely allowed visits from any friends or family.

What’s not adding up for the folks we spoke to is this … they say the facility is highly regarded and the staff has a sterling reputation. They say it’s very expensive — the best money can buy — and they don’t believe the facility would keep Wendy against her will if she didn’t need help.

And, therein lies the dilemma … Wendy tells us she’s fine and doesn’t need round-the-clock monitoring, and several people who’ve spoken extensively with her recently — including Harvey Levin — support that assessment.

As for the day-to-day for residents at the facility … we’re told there are meals, enriching activities, simple exercises, art, entertainment, games, and mentally stimulating activities.

For her part, Wendy tells us she takes her food in her room because she says it’s extremely depressing to be around 90-year-olds with serious health problems.