Return of Reckoning

Does anyone know why I can no longer expand chest 3 in the guild chest even though there is space? I could buy chest 4 and 5. I didn't want that. I wanted to add 2 more rows to chest 3. Strangely enough, in chest 5 there is the point again. I think that's a mistake.

Try disabling your addons and try again.

Without addons, user folder deleted and UI completely reloaded, nothing happens. The mistake remains.

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I took a few screenshots. I didn't want to buy Vault 4 and Vault 5, but row 4, 5 and 6
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P.s. Guildlevel is 31