I have tried the Spanish translation of the plugin. And I really have not had problems with operation. I have noticed some strings are not in the es.po file. I leave images and I found that in the dialog file chain I need to put a space in the sequence 1695
#: dialogs.py:1695
msgid ""
"You are about to remove from a shelf marked as exclusive. This will result"
"in these books being <b> moved </b> to one of your other shelves rather than"
"being deleted from all shelves. <p> Do you want to continue?"
msgstr ""
"Está a punto de retirarlo de un estante marcado como exclusivo. Esto resultará "
"que estos libros se <b>muevan</b> a uno solo de sus otros estantes en lugar de "
"ser eliminados de todos los estantes.<p>¿Desea continuar?"
So that it does not look like in the last image.
The first two images the string is in the core.py file that is also not included in the .po file
If there is any way to manage an updated .po file or any way to do it, do not hesitate to let me know.