It's related with the "Discussions".
I noticed that we do not have any section to add TAGS or Labels while replying to a post.
Something could be added like below:
Thanks for submitting your idea! The only post in a thread that can have labels attached to it is the original post; we do this for a variety of reasons, but the most important is that too many labels can cause confusion and decrease the efficacy of the system in general. We are planning on revamping our labeling system in the near future, so keep an eye out for improved functionality there!
Thanks, @WillM !
