Dahlias 2021

Here's a question for the dahlia aficionado's.

My seed sown cactus dahlias were taken to the allotment and on there first evening there got frosted. About half were affected so I decided to pull these out of their modules. On pulling out the first one I was surprised to see it had already formed a below ground small tuber.
Is there a possibility that they might sprout again from these small underground tubers which seemed unaffected as only the tops were frosted. Or am I kidding myself by leaving them be and snipping the dead tops off.?

I have left them anyway to see what happens.