Open a tab with a page whose title starts with an RTL character. Example:

data:text/html,<meta charset="utf-8"/><title>%E2%80%8Fstring</title>

1. Observe that in the tab bar, the title text is aligned to the right instead of the left
2. Move the mouse cursor around and observe that the title text jumps on hover

The attached clip shows the behavior.

The text should be aligned to the left, like text that doesn't start with an RTL character.
Compare to:

data:text/html,<meta charset="utf-8"/><title>string</title>

Note that when the title is long, this behavior also affects cropping.

This issue is new in Proton.

A better testcase:

data:text/html,<meta charset="utf-8"/><title>%D7%90%D7%90%D7%90</title>

The original testcase used the invisible RTL marker.