No mail templates loading for a language after migrating from 2.4.8 to 3.1.1-4

Hi,
After migrating from OJS 2.4.8 to 3.1.1-4 I notice that mail templates assigned to steps won’t load automatically for Spanish, which was my default locale in 2.4.8 and it is in the new 3.x. However, if I select English from the user interface as session language, they will load.
What could be the reason for this issue?

Thanks in advance for your reply.

Regards,
Juan

Hi,
We have managed to do some tricks so we can continuing. However we’re not getting email selection atuomatically.
When we, say, select a reviewer for a task a review request email is not automatically loaded.
Instead, a list of mail templates is displayed and one is needed to be selected.
We have 88 mail templates, although we think that not few of them have been inherited from previous versions of our OJS instance.
We know that out-of-the box OJS3 includes some 50 templates only.

How could we make automatic selection of template depending on tasks as we had before on our 2.4.8?
Is there a way to clear away all the templates, and load a clean OJS 3 set of mail templates?
Would restoring tables email-template-default and email-template-default-data from a clean installation be a good solution?

Thanks in advance for your reply.

Regards,
Juan