Text Entry "deselect" on unlock: bug, or intentional?

Hi, I noticed something on my Blackberry Classic and was wondering if others have the same thing. Searched and could not find relevant threads, apologies if this was already answered.

If I am sitting on a Text Message or Email reply screen with my cursor in the field for input and I lock the phone, then unlock and try to start typing in the field, it won't let me. I have to first tap or otherwise select the field again and then typing will work. Is this to prevent people being sent "pocket dialed messages" when the phone is accidentally unlocked and the keyboard keys are pressed in-pocket?

Edit: Seems to be a bug? A reboot seems to have eliminated the behavior.

Bingo.

Posted with my  Classic