Couldn't select what polarity to change when using forma

[FreshestVeggies]

Hello,

I just tried using a second forma on my cernos prime and since i didnt have any in my inventory i used the "Buy 3 forma" prompt.Upon getting my formas, one of them was instantly used while not letting me select a mod slot which to alter and leaving my cernos mod slots the same as they were before. The forma count increased from 1 to 2 yet my weapon still only has 3 "V" slots 2 of which are there by default and 1 from my first forma.

Is there anything to be done against the lost forma?