Compare does not see attributes, none! Why?

Hello,
“Compare” is not picking up ANYMORE the attributes I have inserted.
I am using the plugin “WP Sheet Editor” which is able to organize the attributes in alphabetical order, but when I action this the attributes disappear from the Compare tables, while they still show just fine in the product.
Could something be done with “Compare” to pick these attributes?
I am talking with “WP sheets” developers as well in the meanwhile.