In my observation not all videos have translated titles, I'd say about 20~30%. So my theory is that it is either some A/B test from YT, or that the channel owner can opt in/out of the automatic translations.
(Bad for two reasons: (1) badly translated titles, sometimes hilariously so, and (2) the algorithm recommends me videos I have already watched. I guess (2) is because I don't usually watch the last 20 seconds, the static "my last video was", whatever it's called, so YouTube must think I haven't watched the video. Most times, the red gauge below the video thumbnail shows half-full even though I've watched the video minus these 20 seconds. There's still room for improvements...)
[1] https://www.youtube.com/channel/UCg3qsVzHeUt5_cPpcRtoaJQ/vid...
I'd always figured it was an attempt at Youtube SEO - matching keywords in different languages with the same content.