There are too many casino elements in this game.
Think on forging, we try to forge and some get a failure while others are successful in first attempt. Removing a perk from an item and some need numerous attempts to get the perk they want, while others get it in a few or even 1 attempt. Opening cof during conquest and war seasons is one of the most hated casino element. Be unfortunate and pay 15-45 gems for the skulls, while fortunate ones don’t need to spend a single gem. It’s even worse when it happens several times in a row.
We can go on with this, when we open chests, some find useful items, gems and stuff that helps, others find useless items, 1-2 pearls and even 1-2 vouchers. The list goes on and on, so I don’t go into details for runes, hidden treasures, applying runes and other stuff.
In this situation you describe, it’s only an attempt to lure you in, applying another rune of the same level and type to get a better value.