Happy to submit a patch for this but first wanted to discuss it to make sure there's agreement.

(defun tab-bar-select-tab (&optional tab-number)

...

            (when wc-bl  (set-frame-parameter nil 'buffer-list wc-bl))
            (when wc-bbl (set-frame-parameter nil 'buried-buffer-list wc-bbl))

What this skips is that if either the originating window-configuration buffer-list or its twin is nil, that the frame's parameters are not properly reset to nil.

This is a function that we've had to work around in an ELPA package by advising tab-bar--tab to first clear these frame parameters before tab-bar-select-tab goes to set them when selecting the specified tab. This avoids the bug, but is annoying. This advice has been in place for three years without issue.

The patch would eliminate the 'when' conditions.

What do you think?

-Stephane