@ryanmadden, can you supply us with a version that opens without an iframe? That makes it impossible to use the automation inspector, unfortunately.

Actually, @ryanmadden, the smaller the testcase file, the better.

I can confirm that this sample page with NVDA 2017.4 in Firefox 52 and Chrome Canary 65.3299.0 on windows 10 does not report the proper number of items in the select box. It may be because of missing or invalid aria.

This page opens the same demo without an iframe:
https://google.github.io/closure-library/source/closure/goog/demos/select.html

I'll try and reproduce the behavior with a simpler component.

Although ChromeVox behaves differently with this component on ChromeOS and e.g. MacOS I believe the structure of the Closure component may be to blame.

If you investigate and are satisfied feel free to close this issue.

Minimal repro case: https://www.w3.org/TR/wai-aria-practices-1.1/examples/menu-button/menu-button-actions-active-descendant.html
Screencast: https://drive.google.com/file/d/1sz7raDn7j4mM8TvkcvXzwgcYURiGkiy5/view?usp=sharing
Chrome Version: 62.0.3202.97
OS: Chrome OS

Thank you for finding a simple repro case.
In Chrome Canary 65.0.3299.0 on Chromeos, Chromevox does not read the selected option when the menu opens, it does work properly with arrows, announcing options and their position (1 of 4, 2 of 4, etc).

Steps to repro:
# With Chromevox running on Chromeos, visit https://www.w3.org/TR/wai-aria-practices-1.1/examples/menu-button/menu-button-actions-active-descendant.html
# Press the 'Actions' button
# Notice that Chromevox doesn't announce the current option

Expected: Chromevox should say 'action 1' when the menu opens

Actual: Nothing is spoken. To speak the selected option, the user must navigate away from and back to the option. Using down and up arrow for example. 
This makes it slower when the user would like to choose the selected option

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/130d110e4f568f61ed124dec48dedbf80d3588de

commit 130d110e4f568f61ed124dec48dedbf80d3588de
Author: David Tseng <dtseng@chromium.org>
Date: Thu Feb 01 22:16:56 2018

Audit ChromeVox for active descendant support

This adds active descendant to a few output rules that should have it.

Note that explicitly including the active descendant in these rules makes it possible to continue to see the entire output rule as a whole. This makes it possible to provide more intelligent output based on @message_strings, if desired.

Bug:  781840 
Cq-Include-Trybots: master.tryserver.chromium.linux:closure_compilation
Change-Id: Ia3f8bb0e6613d55e080be7b6eccfbdf0ee35033e
Reviewed-on: https://chromium-review.googlesource.com/898023
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Commit-Queue: David Tseng <dtseng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533835}
[modify] https://crrev.com/130d110e4f568f61ed124dec48dedbf80d3588de/chrome/browser/resources/chromeos/chromevox/cvox2/background/output.js