iPad Pro Won't Dismiss Software Keyboard When Entering Text With Hardware BT Keyboard

I use an HHKB bluetooth keyboard for typing in text on my iPad Pro. As of tonight, in all apps, the software keyboard no longer disappears when I switch to the BT keyboard. Prior to this, the software keyboard disappeared when I connected the BT keyboard, and the software keyboard reappeared when I disconnected the BT keyboard.

I've been using iPad Pro since the early days of the M1 version, and this is the first time I’ve had this problem. Yes, I've rebooted several times. No, none of the accessibility "show keyboard" switches are on. No, 'full keyboard access' is not on. This is iPad OS 26.1 on an 11-inch M4 iPad Pro.

Also, see the picture. When I try to type something in the settings search window (upper left), because the keyboard won't go away, the pop-up menu hides the search text.