I don’t think it’s a bug. They’re spaces reserved for homekit devices. It’s bad design that they don’t disappear if unused but it’s not a bug. I have 4 devices there, 2 Apple TV’s and 2 homepods so I just have 2 blank gaps in that row instead of an entire empty row.
Do you have the ‘show home controls’ option on in your control centre settings? It might default to off or not put the placeholder spaces in if you don’t have any HomeKit devices.I don’t have any gaps or any HomeKit stuff