When there are a lot of opened tabs, some of which are pinned, at some point of time when tab bar scrolling is disabled and pinned tab is active, there is no possibility to switch to the tab at the end or to create a new tab because some part of the tab bar is overlapped by search icon.
Last time this happened when I clicked middle mouse button on the link being on a regular tab (that action created a new tab island) and then switched to pinned tab.
This is long lasting issue that persists since tab island was introduced or even older.