Redaction codes not disappearing from redaction boxes once unselected

Acrobat Pro DC:
When I create a redaction box and apply an incorrect code, I used to be able to CTRL+Z or unselect through the same means to remove the code. The code used to disappear and leave the redaction box blank but now the code remains on the redaction box and only disappears once another code is applied. 

In my work not all redaction boxes require codes so a blank box is preferable and this just adds unnecessary rework. Is this a glitch or a problem that can be fixed?