I am having the same problem. After using aUST on Mirror Finance, my deposits on Anchor reads $0. Have you found a solution? or Who to contact to get this fixed?
The Anchor WebApp only tracks for your deposits (aUST) held by your account. By using your aUST as collateral on Mirror, you’ve transferred your aUST over to Mirror protocol (technically tokens are now held by Mirror protocol and not you), and thus the deposit balance is not shown on the Anchor WebApp. The deposit balance should show up once you withdraw your aUST from Mirror to your Terra account.