Hi, I also recently encountered this problem, yesterday.
I think it's caused by this feature introduced in 4.0:
I guess that an image without any 'alt text' uses the substitution reference. Which then ends up in the .po files
As a workaround, I have added an empty ':alt:' option to each image directive in the rst file. It's some work, but I found the strings are not longer present in the po/pot files.
.. |grid-manual-actions-action-trigger| image:: some_image.png
One could debate if the current behavior is a defect (from my point of view, I'd say that