Actually, it is now working. Something I enabled in the bot's permissions last night made it start being able to @mention users. I'd noted that using @here and @everyone worked. It was just that @hepcat72 was not working. I also noted that I could @mention myself manually.
There's no obvious permission setting change that I can attribute it to. I enabled a bunch of permissions and re-invited the bot, hoping that something would fix it... and it did. I'm not sure if this is completely a problem of the bot or the node, but regardless, I just won't mess with it anymore.
