can't deposit tzBTC into an existing tzBTC/uUSD vault on youves - works with other wallets

[djangobits]

Hey there,

one of the youves users reported this and I am able to reproduce the issue:

Describe the bug (current behavior) If a user tries to deposit tzBTC into an existing vault (uUSD with tzBTC collateral), the transaction does not appear on chain and Kukai shows the transaction group as unconfirmed.

To Reproduce

1. get some tzBTC and connect Kukai to app.youves.com
2. go to borrow, select uusd to mint and tzbtc as the collateral (or go here directly: https://app.youves.com/uusd/tzbtc/tracker-v3/detail/tz2BCZNoy6RjSXdU4GPkaxqvypNCKHT3jM3q) and use half of your tzBTC to mint some uusd to create the vault at first. This transaction usually works using Kukai and a new vault will be created on youves
3. try to add additional tzBTC as collateral to this vault by clicking "deposit". Kukai will create a transaction group but it will never appear online and stay unconfirmed.

Expected (correct) behavior Transaction should appear onchain, tzbtc collateral should be added

Screenshots and/or logs

Environment: Device: MacBook Air M2 OS: MacOS Sonoma 14.1.2 Browser: Chrome

Additional context

A) I tried to increase gas, for this transaction, which didn't help

B) it works with temple and airgap

C) The operation group that is created by the youves frontend usually includes:

1. an approval call to the tzBTC contract to spend 100000000000000000000 tzBTC
2. the deposit call to the uUSD engine contract
3. another approval call to the tzBTC contract which sets approval amount back to 0 tzBTC

Kukai seems to add an additional approval in front of it, maybe that's the reason?