Unable to create diff files – Error: EISDIR

[aguavisual]

After upgrading from 0.11.x to o.12.x
I am getting the following error, every time I save or I try to create diff files.

Failed…
Error: EISDIR: illegal operation on a directory, read
'/users/[…]/[sketch_files_path]/.exportedArtboards/[file_name]/input'

It seems the problem is with the name of my symbols in the document:

input/primary-btn
input/alt-btn

After some searching, I found this:

"EISDIR means that the target of the operation is a directory in reality but that the expected filetype of the target is something other than a directory."

Is there a way to solve this problem or is it a bug with the plugin?
When I revert to 0.11 I have no problems.

Sketch version 65.1
macOS 10.15.4