Delete hide characters

Hi everyone,

I added a new column called "Lote/Descripción" and works fine.

But, when I try to "fill down" that column, nothing happens

So, I copied that column in excel to find out what's going on. As you noticed, excel tells me there is something in the cells that are supposed to be empty and the function "len" does not recognize any character.

I understand why "fill down" does not work at this point. But I do not understand why language M does not respect my formula

if Text.Start([#"DESCRIPCION/#(lf)DESCRIPTION"],3)="LYP"
then
[#"DESCRIPCION/#(lf)DESCRIPTION"]
else ""

I hope someone can help me with this issue.

Regards!