"Export as" changes file name

Looks like a workaround is to use File > Export > Save for Web (Legacy) instead. That did not convert the # when I tried it, that probably depends on the filename compatibility preference setting inside Save for Web.

The problem is that Export As seems to stick closely to industry filename compatibility recommendations and reject the # , and I haven’t found if that can be changed. Why is Export As so picky about # ? Because it appears that putting a # in a filename is generally considered not a best practice and may lead to problems. I did a quick search in Google (link below), and it appears that # is one of those characters that should not be included in filenames because some file systems might choke on it, or interpret it in a way that you don’t expect. Similar to how a slash or colon in a filename can break filename paths.

https://www.google.com/search?q=hashtag+allowed+in+file+name