I just noticed a bug with the follow button preventing you from following a post. It has been asked before here: "follow" link glitches to "You’re no longer following this question"

Steps to reproduce

1. Open any question
2. Wait for someone to post an answer (or do it yourself in a new tab)
3. Click on the button which appears: "1 new answer to this question"
4. Try to click any "follow" button on the page
5. Ajax will trigger two requests, both for follow and unfollow

When I say the dynamic AJAX loading I mean this button:

When you have Network tab open you can see two requests made:

First response (POST https://stackoverflow.com/posts/62117670/vote/21):

{"Success":true,"Warning":false,"NewScore":0,"Message":"\r\n<div class=\"s-popover p0 py12 js-following-confirm\" id=\"divFollowingConfirm-62117670\" role=\"menu\" aria-hidden=\"true\">\r\n    <div class=\"s-popover--arrow\"></div>\r\n    <p class=\"bold mb4 px12\">You&#x2019;re following this answer</p>\r\n    <p class=\"mb12 px12\">You&#x2019;ll receive notifications when there&#x2019;s activity on this post</p>\r\n    <p class=\"mb0 pt12 px12 bt bc-black-3\">\r\n        <button id=\"btnUnfollowPostConfirm-62117670\" type=\"button\"\r\n                class=\"s-btn s-btn__link js-unfollow-post-confirm js-gps-track\"\r\n                data-gps-track=\"post.click({ item: 16, priv: 17, post_type: 2 })\">\r\n            Unfollow\r\n        </button>\r\n    </p>\r\n</div>\r\n","Refresh":false,"Transient":false,"Info":false}

Second response (POST https://stackoverflow.com/posts/62117670/vote/21?undo=true):

{"Success":true,"Warning":false,"NewScore":0,"Refresh":false,"Transient":false,"Info":false}

I use Google Chrome browser.

Google Chrome   83.0.4103.61 (Official Build) (64-bit) (cohort: 83_61_Win)
Revision    94f915a8d7c408b09cc7352161ad592299f384d2-refs/branch-heads/4103@{#561}
OS  Windows 10 OS Version 1909 (Build 18363.836)
JavaScript  V8 8.3.110.9
Flash   32.0.0.371 C:\Users\Kamil\AppData\Local\Google\Chrome\User Data\PepperFlash\32.0.0.371\pepflashplayer.dll
User Agent  Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.61 Safari/537.36

I am able to reproduce it multiple times, so if others can't reproduce it you can ask me for more details about my environment to help with debugging.