This looks like a gadget problem.
The table of contents displays at this URL: https://zh.wikivoyage.org/wiki/%E8%87%BA%E6%9D%B1%E7%B8%A3?safemode=1

Please remove:

/* 讓橫幅的章節標題文字可以繁簡轉換，直接抓取真實章節標題文字 */
$('.toctext').each(function(i, e) {
    $(e).text($($('.mw-headline').get(i)).text().trim())
})

from https://zh.wikivoyage.org/wiki/MediaWiki:Common.js

Sorry... the title is wrong, we need hidden the table of contents, not display in page left, Wikivoyage page banner has table of contents, we need as like other wikivoyage language version , not display the table of contents in page left.

@Yuriy_kosygin that is https://phabricator.wikimedia.org/T295003 and I'll be backporting a fix for in 2 hrs and 30 mins that should address that issue.

In T295227#7489787, @Jdlrobson wrote:

Please remove:

/* 讓橫幅的章節標題文字可以繁簡轉換，直接抓取真實章節標題文字 */
$('.toctext').each(function(i, e) {
    $(e).text($($('.mw-headline').get(i)).text().trim())
})

from https://zh.wikivoyage.org/wiki/MediaWiki:Common.js

Fixed in https://zh.wikivoyage.org/w/index.php?title=MediaWiki:Common.js&diff=prev&oldid=177894

In Yandex, Google Chrome and Microsoft Edge browser to see 北竿, the left TOC same still display! Wikivoyage page banner have TOC, we Wikivoyage no need this TOC, Please remove left TOC!

I don't see the table of contents here:
https://zh.wikivoyage.org/wiki/%E5%8C%97%E7%AB%BF?safemode=1

Is it possible an old version is being cached?

@Yuriy_kosygin: Cannot reproduce the problem.