Problem when manipulating Traditional Chinese page of the website

I have tried to copy all plugins from English to zh-hant page and edited some of the contents. I accidentally copied the plugins twice and tried to delete them. Then, I found there might be something wrong with the editing process in zh-hant pages.

Reproducible: always

Reproduce steps:

1. switch to 'structure mode'
2. click the hamburger icon and press the delete bottom

Actual result:

1. django reported error and nothing changed.
2. But if I changed the language in the "error" page from above step, I can then delete the page successfully.

Expected result:

1. the manipulation of zh-hant pages should be as normal as other languages

I have recorded a screencast to show the problem at https://www.dropbox.com/s/cmybq3tgqukj2iw/inkscape-edit-redirect-error-zh_hant.webm?dl=0