The list of statblocks can be viewed from the sidebar window. When hovering a statblock the trash bin shows up. Once clicked the confirmation comes up and when that is clicked the statblock is deleted permanently. However if the statblock is added to a folder the pressing the checkmark for confirmation does nothing. Statblocks can be deleted as expected if they are moved out of the folder or if they are deleted from the statblock editor.
A fix for this was recently deployed. Can you check if the issue is still occurring? (Please hard refresh)
Can confirm that this is resolved! Thank you for your work Xuroth! :)