Can be tested using: http://en.wikipedia.beta.wmflabs.org/wiki/Special:ContentTranslation?from=id&to=ms&page=Bahasa&targettitle=Bahasa

// Clicking on the link that exists only on the source and not for the target, turns the source link red.

This is expected behavior if the link in the source article is indeed a red link. We show it as blue. when clicked we check if it exist or not. If it does not exist we turn it red. We are not doing this check for all links in source article without any trigger because of performance issues. See https://gerrit.wikimedia.org/r/#/c/163100/ and https://wikimedia.mingle.thoughtworks.com/projects/language_engineering/cards/4373

// After selecting a text in the target that previously displayed a link, the link card is not displayed (inconsistent; sometimes displayed)

Duplicate of T85930

// Clicking on the source link automatically adds the link in the target (not consistent)

Tracked through T85992