Fonts near-unreadable on macOS Mojave

I am using Qt Creator 4.8 beta 2 on macOS 10.14.1 on a laptop. With the built-in retina screen it looks fine. On an external low-res screen, the fonts are almost unreadable.

As I remember, this problem was not present in 4.8 beta 1. It is certainly not present in 4.7.2.

I attached two screenshots comparing 4.8.0 beta 2 and 4.7.2.

I have subpixel antialiasing re-enabled (on Mojave it's off by default), as I find that this improves the readability of fonts on the external screen with several other applications. Read more here: https://code.visualstudio.com/updates/v1_28#_miscellaneous