According to the catalog, Colombian non-magnetic 50 pesos had been produced until 2006 (https://en.numista.com/catalogue/pieces1073.html), and magnetic ones - since 2007 (https://en.numista.com/catalogue/pieces47429.html). My coin has the date 2007, but it is non-magnetic, and has weight 4,65 g - even more than all the other non-magnetic 50 pesos.
Please everyone check your 50 pesos 2007, if they are magnetic or not.