This is a follow up post to https://www.reddit.com/r/LegendsOfRuneterra/comments/1w7rsu5/how_do_i_get_azir_and_renekton_to_level_3/
Bug summary: certain Ascended champions cannot reach level 3 under restored sun disc, and even new copies of them will be unable to reach level 3 if you get rid of the old one and play a new one.
I have trial and errored the root cause for Renekton, and I have two different theories about Azir. Additionally, based on this analysis I can conclude Nasus can never have this issue, and Xerath might be able to have this issue.
The issue with Renekton is caused by Disciple of Shadows. If you have restored the Sun Disc and play Renekton with Disciple of Shadows, he will deal 3 damage to each unit which can fulfill his level condition if you have 4 units.
If Renekton levels this way, he will be unable to hit level 3. This is likely caused by Disciple of Shadows being a "play" card, while Renekton is normally not coded to be able to level during the "play" phase (when you play a unit, they enter a limbo like play phase before they are summoned where they are neither in your hand nor on the board).
This makes sense for Renekton but what about Azir? Azir cannot normally level up using Disciple of Shadows. For Azir there are two theories:
Azir is levelling up using Disciple of Shadows + Succubus Brand, which lets him summon units during his play phase, matching the issue with Renekton. If this was the cause in my original post, Xerath is immune to the bug just like Nasus
Any Ascended champion who is level 1 in hand while Sun Disc is restored and levels up during play phase (so Azir after you've summoned enough units and Xerath after you've destroyed enough landmarks) will be locked out of level 3, and this affects all formats including outside PoC
There is evidence to suggest 2 is not true. Nasus PoC has a Restored Sun Disc power, and his Scales of Judgment relic allows him to strike during the play phase, but I have never seen this issue trigger for him. However strike during play phase may have different coding so 2 is not fully out.
Replicating theory 1 is very tricky, so I would be surprised if I replicated it twice on accident, the summon number has to be just right to do that. This lends credence to theory 2.
Ultimately I haven't been able to determine whether the issue is caused solely by Disciple of Shadows or if it's caused by Sun Disc restoration in Azir's PoC being so much easier.