Thanks a lot @Salva for fix the Stock Central 🙂
For my products SKU I agree that their must be unique, OK!
Instead, I don't choose the suppliers SKU and I find myself in difficulty because in some cases they are the same and I have no way of inserting them elsewhere... (maybe you can leave a message but accept the values, don't exclude them in the beginning)
I also have a shop with Prestashop and there I have the possibility to insert the same SKU for the suppliers (on Prestashop I also can to assign more suppliers for the same product. Here on WC this possibility does not exist.. but it's a nice feature)
Regards