Round corners sticking

[Albeitadrift]

I have an issue with a shape, it's not got rounded corners, but displays the stroke as if it does, if I turn them up they round as expected, then drop back down as I slide the handle at the corner and as it notes it gets to zero they snap and display as rounded again. 

I've screen recoded the issue, but I'd seemingly have to host it somewhere to show here. 

I've uploaded a screen cap, you can see it is 0px above. 

Thanks in advance! 

[Monika Gause · Accepted solution]

Can you show the appearance panel?

And yes, please put the recording somewhere. Probably Wetransfer

[Albeitadrift · Accepted solution]

Genius!
It does indeed have a round corners aspect in the Appearances panel. 
I figured this was overidden when adjusted the aforementioned way. 
Lessons learnt! 

Appreciate the swift response too, Monika! Legend! 

[Monika Gause]

I'm glad you could solve it. 

What gave the Round corners effect away is the non-even radius of the small curve in the bottom left. It's not a semi-circle.