bug#49742: 28.0.50; previous-single-property-change sometimes wrong?

[Eli Zaretskii]

> From: "T.V Raman" <raman@google.com>
> Cc: 49742@debbugs.gnu.org
> Date: Mon, 26 Jul 2021 10:19:13 -0700
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> 
> See below for the results you ask. It does not explain itself because
> property 'face is nil at positions  30 and 29.

Yes, it's nil.  So that is the last position before 'H' where the
value of the 'face' property changes -- from transient-inactive-value
to nil.  Which is why the function returns that position.

If this still doesn't explain the results, please tell what is missing
from the explanation.