Hello @ofir.kuperiu,
Thanks for your report and trying to make Boundary a better product!
The Boundary controller should be running a periodic job that monitors all your credential store Vault tokens, and renews them at about half way to their expiry regardless of having credentials attached to the token. If the only credential store you have is that one with the 20m token, I would expect it to be renewed every 10 minutes. This does, however, have a requirement that your Boundary controller and your Vault server are up and running consistently to be able to perform the renewal.
We have received another report similar to yours, I have not been able to reproduce an issue with token renewal on my side yet. I was planning to spend some cycles next week looking into this.