Anyone know why my wall has created this gap?

I just noticed this gap, and I don’t know why it appeared. Would anyone know how to fix it?

Hi @Clayton_Hull, could you attach the 3dm file so we can better figure out what’s happening?

Here you go. WeTransfer - Send Large Files & Share Photos Online - Up to 2GB Free

Thanks @Clayton_Hull,
I can see the upper wall (A) seems to be extended to the lower wall (B), and this is causing some intersection issues.

Try to unextend the wall A and then you can move it next to the lower wall (B) so there is no gap anymore.

I will give it a try. Thank you so much!