The close button has a circle around it in Wayland GTK3 apps that use client-side decorations (verified in Firefox, Gnome Calculator). Also, in Google Chrome, the window buttons will be white when using a the Breeze light theme. The window buttons appear normally when running these apps in XWayland or a Plasma X11 session. This happens with both the KDE Breeze theme and Manjaro's Breath theme. I have logged out and back in after changing themes.
Linux: Manjaro with kernel 5.10.74
(available in About System)
KDE Plasma Version: 5.23.1
KDE Frameworks Version: 5.87.0
Qt Version: 5.15.2
*** This bug has been marked as a duplicate of bug 443919 ***