Mail still filling up bank slots

Hi, I thought I saw a note about this somewhere before. I am unable to store mail anywhere except for in my inventory and in my bank.

My bank is maxed out because I have 115 pieces of mail mail in a chest in my bank. I am able to add more mail into my bank, but I can't use my bank for anything else.

Is this working as intended? Should I be destroying each piece of mail?

Thanks!