Tab bar and navigation bar color

Question

Since upgrading to Xcode Version 13.2.1 (13C100), I've been having display issues with some of my view controllers. They look to all have the same properties, but some display with the correct colours in the tab bar and navigation bar and some do not. If it's displaying correctly and I add a view to the view controller, it stops working. I'm really baffled as to what has changed and why they're different.

They should look like this.

... but many of them (not all) now look like this, after the upgrade.

Any idea what has changed?