I just confirmed it. Yes, the visualization of a profile (the fediverse community located in lemmy.world in this case), will vary depending on the instance being used to access it. It’s really a pity though. Things like that should be transparent.
IMHO, whenever the user searches explicitly for a profile/toot/post/whatever, all relevant data should be fetched as well.
If such setting is implemented, please don’t limit it to a single language. Many people knows multiple ones while still wanting to filter out all the other languages they are not familiar with.