‘default’ button remains selected after deselecting it

Hi again,

Once I select the ‘default’ option on a variable product (to display countdown timer of this variation when customers have not selected any variation) I cannot unselect it. I mean, I can, but when I save changes or update the product it automatically goes back to being selected. This only happens once it’s selected, if it wasn’t selected in the first place it stays unselected.

Please find the screencast to this issue in the following link:
https://drive.google.com/file/d/1qZsahQsz764rEOhzs0ClTNg0XukoJoq1/view?usp=sharing

Looking fwd to your comments.