It's not a matter of testing. It's just doing the work right. I used to get lazy and make these mistakes also. It really isn't the persons fault, just a learn from it thing.
The problem being on the regular side views, you have more room from head to next view to do more to the hat
Most people just rotate>copy>paste it on the pulling side views
The pulling side views have less room from head to next template which is why you see that overlap on the template.
Solution for this hat would be to make the strings fall downward with gravity while pulling, but seeing as era has no pull or push as of yet, you could just delete that view or shorten the string
As for the back view, that's a simple fix