I noticed this on my druid. I was level 16 when I tried pulling Sunfire into my neron action bar for the level 16 skill but instead it pulled the level 32 skill which was still unavailable/gray to me in the spellbook because of my level.

Same with my DK. In the blizzard UI the skill "Death Strike" is available as soon as you make the DK n therefore has no listed minimum level requirement. But again, when I pull that skill into my neron action bar, it places a level 68 Death Strike every time. When I hover over that skill in the spellbook it says underneath the spell in the spell description "not yet equipped" although it's sitting in my action bar.

this must have been from bfa? i haven't noticed this issue in shadowlands. is this still an issue for you @gylva?

This is an issue in Classic where they still have spell ranks. It is probably still an issue. We don't have any code in place to search between spell ranks

Interesting. Ok. I'll look into this. I think I can fix this without much of a problem. For the time being just edit the macro to read "/cast sunfire" and that will get you going for now. Out of curiosity, what do the macros that Neuron generates for Sunfire and Death Strike read in their broken state?

The sunfire macro worked without issues.
The neuron created macro read " /cast Sunfire() "
Death Strike reads in the macro " /cast Death Strike() "

I should note that the /autowrite line seemed to prevent me from casting spells after shapeshifting in druid form or sometimes simply stopped working after I've been idle for 5mins without ever having cast a single spell. After I removed /autowrite from every spell it worked as intended.

Furthermore I noticed that in the Frost spec for DK the skills Frost Strike, Howling Blast and Obliterate all read as "not yet in the action bar" within the spellbook although all 3 are in my neuron action bar!

Strange so the macro read "/cast Sunfire()" but wouldn't work, but manually typing out "/cast sunfire" does work? I'm confued as to why the first won't work. I'll look into it. The #autowrite should be pretty much invisible to the game being able to cast the ability. I have no idea why that would be causing errors

Nono, the macro wasn't the issue.
The issue is dragging the spell from the spellbook and it showing as a lvl 68 skill (I'm lower level) and thus being unusable. Even though I can only pull the low level spell it still somehow shows as level 68 one. But manually going in and creating a macro to cast a spell works like a charm.

Sorry for the confusion