When a new tab is created under mini toolbar mode and compact mode, the design of highlight ring around the address bar might seems a bit conflicted with the "Search or enter website name" text. The highlight makes the space in the address bar so packed up that the hint text does not fit in comfortably. Also, the highlight ring does not cover the edge of the address bar (probably due to liquid glass design), it seems a bit weird;

I am sorry that I am not a professional designer so I can't give any real advice other than stating "this looks weird". I hope somebody who is good at this can sort it out.
Version 0.99.138-rc (WebKit 623.1.8.0.0)
Tahoe (26)