The first post in a topic can be edited once but when that happens, the Poll setting "Options Per User" is set to 0 despite the value being 1 during the first edit.
Steps to reproduce:
1. Install latest develop
2. Edit First Post and submit.
3. Edit first post again, try to submit it.
4. First, nothing will appear to happen. Click on the Poll tab and hit submit again.
5. JS popup will state "Value must be greater than or equal to 1" for the Options Per User setting.