Scrolls scarce for certain Legendaries

[steep hill]

I have been having trouble upgrading three of my Legendary units, the Artillery, Mage and Balloon Buster. As I understand, normal units receive a single scroll with each placement, and scrolls for Legendaries seem to be confined to Quests, chests and event-progression.

However, I’ve only seen scrolls for my Amazon, and Templar that seems to receive the lion’s share every event – I rarely see scrolls for Artillery and Mage in chests, and just one, ever, for Balloon Buster.

Are scrolls for these three units really this rare, or is this a bug?

[zinc topaz]

Aside from quests and battlepass rewards:

• Amazon and Blob are available primarily through their labeled Dungeons key chests.
• Spy is available (exclusively?) through Clash quests and Clash bone chests.
• OrcSlayer, Warbeast, Mage, Artillery, BalloonBuster, and Templar are available through skin chests as a replacement if you would receive a duplicate skin that you already own. This includes (but not limited to) Loyalty Skin chest, Clash bone chests with skins, Dungeon 10 key chests with skins, and event currency chests. Press the (i) on chests to see if skins are available. Typically this replacement is 5x of a random legend from that list. The recent Dungeon key “2020 Odyssey Skins!” Chest gives only 1x legendary scroll after collecting all skins. Each clash event typically has 4 available purchases of a chest with 1 guaranteed skin, and usually this works with this replacement rule, but sometimes 🐛.
• OrcSlayer, Warbeast, Mage, Artillery, BalloonBuster, Templar, and Necromancer are available as secondary chances in Dungeon key chests. Amazon and Blob also have a secondary chance in the other unit’s labeled chest.
• The Dungeon key store periodically (weekly?) has 1-time purchase of 10x scroll of a legendary unit. I currently see Artillery; I assume it is the same for everyone.