isSubmitting issue in NextJs tanstack Form with demonstration repo

Hello there!

I love tanstack form but the isSubmitting is driving me crazy.

It's such a simple use case still I was able to spend 3h trying to figure out the difference between two repos, one working one not.

https://github.com/ralf-boltshauser/tanstack-form-isSubmitting-issue

I created a demo repo where I showcase the issue, please clone, install and see the demo.

Can anyone tell me why I need to use onBlurAync validator in order to make isSubmitting work???

Of course I could manage isSubmitting myself but that feels wrong. I want to use the tanstack isSubmitting...