500 while trying to post answer (tracking issue)

[cellio]

Following up a conversation in Discord:

A user got a 500 and multiple "failed to save draft" messages while trying to post an answer. Refreshing and trying again fixed it. Don't know if these are related, but:

• The user had another post in progress.
• The server was under high CPU load at the time.

Error:

  NoMethodError: undefined method `[]' for nil:NilClass

                   PostType.find(params[:post][:post_type_id])
                                              ^^^^^^^^^^^^^^^

From /var/apps/qpixel/app/controllers/posts_controller.rb:43 in create