Mona Lisa style painting

We had this at one of our larger estate sales but the client's family did not want to sell it as their deceased mother felt it was important. She had taped an article about Mona Lisa type paintings to the back of the frame. I believe this work was originally on canvas then laid down. Perhaps to fool someone into thinking it was older or maybe it is? Blacklight goes wild on this piece and it just seems 'weird'. The left eye is weird as is the fingers. I am used to seeing varnish and over/inpainting but not sure what to make of all of this. The client had this re-framed a few years before she died. This client was extremely well off - important family. I'll include a link to video of the work under blacklight. https://youtube.com/shorts/h1i0SgCwZ80?si=lDIvLVD9u6Oq5dl4
I do have the measurements but I have to go through pages of notes which are in my truck and right now it is sleeting and snowing in Georgia!

 

Think this has some age to it but think 20th century. If antique, only barely so. Seems to be an amateur work and I don't think of much consequence.

 

The dress and hair (and cap) look 1840s, which doesn't rule out a later copy.

Either the sitter had a deformed arm and hand or the painter couldn't paint arms and hands. The face used to be more round.
Maybe the way the UV lights up the surface has something to do with an inexpert cleaning method?

 

I don't see anything that would make me think that's old old. Might be a copy of something. Eye brows are very 1930s. And distoration of hands and arms leads one to believe not a fully trained artist.

Debora