I have run into a weird issue or bug and I can't seem to find information on it anywhere. I can't seem to unlock the Advanced Armor perk in the Smithing Tree. At first I thought it was because I had a mod running that was called "uncapped perks" or something but I deleted that and went back to the vanilla perk system and played a new game. My smithing is at 50, I've unlocked the Elven Smithing perk and it is not lit up. Did Dragonborn change the requirements or something because I've never had this issue before? On other playthrough, with that uncapped mod, I got it up to 100 and had all but Glass and Advanced unlocked and it still wasn't lit...

Am I missing something or is this just a common bug that I happened to miss the last 5,000 playthroughs because I never really focused on smithing?

I've never had this issue, I'd check all of your mods for the culprit. What mods are you using? Is your load order good?

List your mods first it must be a mod that has changed the Requirement for advanced armor perk by default it requires elven smithing to be unlocked first but since you have that perk it must be a mod conflict that has changed it to something else for like orcish or dwarven or something similar