For future reference, the team looked into this, and it appears that the interruptions you experienced were specific to your project and a small number of other projects. The vast majority of TRC projects should see much longer Cloud TPU uptimes when they are able to create on-demand TPUs.

I'm sorry that you had such a frustrating time and that we weren't able to sort it out via email while it was happening. If you decide to try TRC again and run into issues like this, please be sure to engage with TRC support!