I am using Brave Browser iOS v. 1.70.1 (133) on an iPhone.
Clicking on the URL address field, just a hair to the left of the Reload button, might sometimes cause a very quick highlight-and-then-an-unintentional-tap on the “X” (cut) button.
You don’t even have to touch the “X” (cut) button. If your finger tip is close enough to the display screen, the screen might sense and click for you.