Wendy Williams Moved to Memory Unit Over Alcohol Issues

Wendy Williams ended up locked in the memory unit of the assisted living facility she's called home for 8 months ... but apparently not because of her dementia diagnosis -- it's because she got drunk in the building's restaurant.

An employee at the facility who has had numerous interactions with Wendy from the time she arrived tells TMZ ... Wendy was initially placed on the 3rd floor of the building, which does not have restrictions on a resident's comings and goings.

Early on in her stay, Wendy went to the top floor restaurant/bar for lunch. Our source says Wendy began ordering drinks and got drunk. She was there for a long time, and when supervisors found out, we're told they were furious Wendy was served alcohol.

Our source says shortly after the incident supervisors decided to move Wendy to the 5th floor memory unit, where she would not have free access to the elevator. The reason ... they didn't want her going up to the restaurant and getting drunk again.

Problem was ... the memory unit was full, so while supervisors waited for a room to become available, they kept Wendy on the 3rd floor but had employees stand guard outside her room so she couldn't wander upstairs.

We're told employees told Wendy the restaurant was under construction and was not operating.

Days later a room became available on the 5th floor and Wendy was moved, and she's been there for months. As you hear in our documentary, Wendy says she only breathed fresh air twice in 30 days ... when she went for dentist appointments.

As for Wendy's memory ... the employee says it's firmly intact, telling TMZ ... "Wendy doesn't have good and bad days. She's the same all the time," adding, "You can tell her something today and 2 weeks later she'll remember it. Her memory is fine."