i18n translations or fallbacks not picked up

[KimonP]

Hi all,

Setup

1. AEM version: 6.5.6
2. We have a website with multiple regions and languages, in the example I provide it's the Mexico/Spanish tree, e.g. /content/mysite/mx/es.
3. We have set up i18n keys for EN and ES locales.

Steps taken + Issues

1. No jcr:language provided in mx/es page, i18n translations rendered fine from ES
2. Switching jcr:language in mx/es page to es-mx, i18n translations rendered fine from ES
3. Removed an i18n translation value from the ES i18n dictionary
   • expected: EN translation picked up, as per org.apache.sling.i18n.impl.JcrResourceBundleProvider config
   • actual: nothing rendered
4. Re-added the missing ES i18n value, i18n translation rendered fine again
5. Added an i18n translation for MX-ES dictionary, i18n translation picked up properly (as mx/es page has mx-es locale set at this point). All the rest of the i18n translations are picked up from the ES i18n values
6. Removed the i18n translation from MX-ES dictionary
   • expected: ES translation is picked up
   • actual: nothing rendered

It was my assumption that the fallback mechanism in general is 

1. Exact locale (e.g. MX-ES)
2. Closest locale (e.g. ES)
3. Default fallback (e.g. EN)

However this does not seem to work. Any clues or workarounds on that?

Thank you in advance.

[rawvarun]

https://experienceleague.adobe.com/en/docs/experience-manager-65/content/implementing/developing/com... will be helpful.