Bug: "Follow this ticket" does not work almost synchronous

Environment: Chrome Version 88.0.4324.150 (Official Build) (64-bit), Linux.

What I Got: When I click "フォローする" button on a ticket, the result seemed not to been saved correctly. I got "Reload site: Changes you made may not be saved." message from chrome when I try to reload the page 30 secs after clicking, and the following was cancelled if I reloaded. I can manage to save the result with the following steps: 1. click "フォローする" button; 2. click "オープンとして送信" button with empty comment. (This is very hacky...)

Expected behaviour: Almost synchronous follow, like "self assign" button of GitHub and "Follow this thread" button of Slack.