TLDR; Update CookieDropBlock if you want to keep using it.
Over five years ago I released a simple tool called CookieDropBlock who's sole purpose was to allow editors to create a block to drop a cookie for an end user. You can read more about it here: https://www.david-tec.com/2015/09/cookie-drop-block-for-episerver/. This has worked largely untouched for all this time.
However there is a bug that will affect anyone who is using it today.