Hi @Yannmaco, thanks for taking the time to report this!
Unfortunately this report lacks some information.

I go to https://zh.wikipedia.org/wiki/Wikipedia:首页 and under 其他语言 (In other languages) on the left I do not see that first line.
I do not get those yellow or green dots in front of the language names either.

If you have time and can still reproduce the problem, please add a more complete description to this report (a list of steps to reproduce which leave no room for interpretation what to do, describing actual results and expected results after performing the steps to reproduce, attaching or linking to a public testcase).
Do you have anything enabled on https://zh.wikipedia.org/wiki/Special:参数设置 under 小工具 (Gadgets) or 测试功能 (Beta features)?
Ideally, exact and clear steps to reproduce should allow any other person to follow these steps (without having to interpret those steps) and see the same results. Problems that others can reliably reproduce can get fixed faster. Thanks!

@Yannmaco @TTO and @Aklapper thank you all again for your inputs. But if I remember correctly, those grey links are handled by ContentTranslation, so it's likely that @Amire80 already asked this issue at T138494

Thank you so much!
I think T138494 that @Amire80 metion before is exactly the same question I met!!