Reference error in material function instance.

A reference error occurs for a texture that is 100% confirmed to exist.

This is a Material converted to a Material Function for use with Landscapes, instantiated and used. However, a reference error occurs for the texture referenced by BaseColor. This happens with any texture.

The strange thing is that I have another instance derived from the same function, but nothing is happening there. It seems that an error occurs when there are multiple instances derived from the same function. Why does this happen?

Error

Please, can someone help me? Why is everyone ignoring my question?