Android Espresso waiting for view, R.id value keeps changing

Question

in many parts of our app we have some videos. and in my tests i am waiting for the video to be finished with this:

onView(isRoot()).perform(waitId(R.id.activity_generic_video_video_control_next, 80000));

waitId() is a function I snagged off of a post here on StackOverflow, and it worked very well for a long time. Now for some reason it's not working and I am not sure when this broke or why.

/** Perform action of waiting for a specific view id. */
    public static ViewAction waitId(final int viewId, final long millis) {
        return new ViewAction() {
            @Override
            public Matcher<View> getConstraints() {
                return isRoot();
            }

            @Override
            public String getDescription() {
                return "wait for a specific view with id <" + viewId + "> during " + millis + " millis.";
            }

            @Override
            public void perform(final UiController uiController, final View view) {
                uiController.loopMainThreadUntilIdle();
                final long startTime = System.currentTimeMillis();
                final long endTime = startTime + millis;
                final Matcher<View> viewMatcher = withId(viewId);

                do {
                    for (View child : TreeIterables.breadthFirstViewTraversal(view)) {
                        if (child.getId() != -1) {
                            Log.d(TAG, "child id " + child.getId() + " vs " + viewId + " vs " + R.id.activity_generic_video_video_control);
                        }

                        // found view with required ID and it's visible
                        if (viewMatcher.matches(child) && child.getVisibility() == View.VISIBLE) {
                            return;
                        }
                    }

                    uiController.loopMainThreadForAtLeast(50);
                }
                while (System.currentTimeMillis() < endTime);

                // timeout happens
                throw new PerformException.Builder()
                        .withActionDescription(this.getDescription())
                        .withViewDescription(HumanReadables.describe(view))
                        .withCause(new TimeoutException())
                        .build();
            }
        };
    }

As you can see, the code loops for a period of time until the view in question is visible. The interesting part is I am getting this output from my log statement in the for loop:

child id 2131363297 vs 2131362267 vs 2131362265

The first # is the ID of the view given why traversing the display tree. The second # is the ID that is passed into the function. The third # is the ID of the same view while referencing the R.id directly.

I can say that at least the 2nd and 3rd numbers should be the same, but they aren't. What's going on? Why is the id value changing?