How to recover from failed stack updates

Hi,

I am trying to update an existing heat stack. In the original stack I have created few vms. Now I want to add more vms to the same stack. I am providing the compute node name where the vm should be launched. At first I put the compute node name wrong and the stack update failed. The newly added VM state is in error in nova list. I again trie to update it with the correct parameters. But it failed. Then I had to delete the stack and create the original one. Then I updated it with the correct template. Then it updated successfully.

Then I simulated the stack failure again and every time once the stack update is failed subsequent updates are also failing. Is it a bug or there is some other way to recover from a stack update? Or else I am missing something? Please help.