If I place alchemy on the ShadowDancer bar and click it then the window will not be opened / closed. Every other profession works.
If I place the same alchemy icon on ElvUI bar it works.

Update the Scorpio Lib to r221, check if fixed.

Replace the spell again, since I removed some modification. I have run a test, it'd open the alchemy dialog.

If still not works, try use macro instead since I can't reproduce it. Or you can join discord.gg/6hD4sdUtgp, so you could run several test codes for a fix

No, it did not help.

It seems for some reason /cast Alchemy does not work for me, others also reported the same issue for different trade skills also. I tired clearing cache, but it did not help, I think it is more of a WoW issue, so if you don't feel like doing some alternative "hacks" to open skill frames then close the issue.

Related forum: https://us.forums.blizzard.com/en/wow/t/command-to-bring-up-specific-profession-window/1360761/6

You can try use the macro

/cast Alchemy
/run ProfessionsFrame_LoadUI();ShowUIPanel(ProfessionsFrame)

click twice if not work. maybe can fix it.

/cast Alchemy doesn't work at all, even if i open the frame manually to "cache" it and then close it.

/run C_TradeSkillUI.OpenTradeSkill(C_TradeSkillUI.GetProfessionSkillLineID(Enum.Profession.Alchemy)) however works every time.

So I just made a macro to open Alchemy, because blizzard fucked something up.

Your macro opened a broken frame after reload:

And opens the last loaded crafting frame when I manually open one (e.g. if I open engineering and close it, your macro will open Engineering).