Add support for localized related posts with LSI

Currently I have a dual language blog thanks to the multi-language-al-folio template, which uses the Jekyll Multiple Languages Plugin. I have enabled the support for related posts with the Latent Semantic Indexer (LSI) as suggested by the documentation. The problem is, the LSI is not calculated based on the localized blog posts as expected.

How can I achieve this? When not using LSI, so the related posts is populated by the most recent ones, it uses the localized posts correctly.

Enabling LSI and checking related posts in a pt-br post: