Control Panel reverts Select field to default value

I'm seeing strange behavior with Select fields in v1.9.2. I set a value for an entry, and it appears correctly on my site (and is reflected if I view the Markdown), but when I return to the entry in the control panel, the field's select menu has reverted to display the first choice in the list. Provided I do not edit the entry, this does not appear to have any adverse effect. However, if I do edit the entry (and neglect to reset the desired value in the select field), the entry then shows the incorrect value on the site and in Markdown.

Here's my fieldset:

hide: true

fields:
  title:
    instructions: "Enter the resource title here."

  content:
    type: hidden

  type:
    display: Resource Type
    type: select
    options:
      - General
      - Engage
      - Manage
      - Quantify

  category:
    display: Resource Category
    type: select
    options:
      - Case Study
      - Whitepaper or Article
      - Webinar
      - Video
      - Product Overview

The resulting front matter for the entry:

---
title: 'PRODUCT OVERVIEW: Optix Manage'
type: Manage
category: Product Overview
summary: Program delivery automation
link: http://content.example.com/file.pdf
link_text: Download
---

And the Control Panel display: