This is an important one to note: If you use the popular Automatic Entity Label module on a multilingual site, it will break your paths because of an interaction with Drupal’s built in object cache. I looked at this briefly a few months ago and ran out of time, but my (badass) colleague bburg figured it out this week.
For now, the only solution is a slow one – we clear static entity caches when we generate multilingual titles. That’s not an awesome fix, but it’s hard to think of a better one without any of the D8 cache tagging functionality. Massive kudos to bburg for figuring this out!
And for those of you keeping score, this is a good example of how to file a bug report for a really complex issue in a really popular module… and follow up until you resolve it.