1. Create a cluster and allocate as much memory for default bucket as server quota allows.
2. Go to manage data buckets page.
3. Press "Create New Data Bucket" button. It will show a message saying that it's impossible to create a bucket since all the RAM is occupied.
4. Press "edit" button for default bucket and decrease per node RAM quota. Don't reload the page.
5. Press "Create New Data Bucket" button again. It shows the same warning message.
6. Reload the page and press the button again. Now it works as expected.