InstructionTarget image load error 403

I was investigating another issue using the Navigation UI SDK. I noticed this error in logcat occurs at every turn in the route, or for each instruction.

I don't see anything out of the ordinary, like a blank icon. But, it could be some images are missing that I'm unfamiliar with.

We're recording logs, and we're currently filtering this out. I'm not clear whether it's indicative of an actual error. Since it's a 403, I wouldn't expect it's something that was retried and succeeded (normally 403 implies it's not retryable).

Also, noting that NavigationOptions.Builder::isDebugLoggingEnabled is false.

logcat output

There is always a pair of these errors.

2020-09-28 14:59:01.894 14884-14884/com.aapmobileedb E/InstructionTarget: com.squareup.picasso.NetworkRequestHandler$ResponseException: HTTP 403
        at com.squareup.picasso.NetworkRequestHandler.load(NetworkRequestHandler.java:51)
        at com.squareup.picasso.BitmapHunter.hunt(BitmapHunter.java:219)
        at com.squareup.picasso.BitmapHunter.run(BitmapHunter.java:175)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:462)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
        at com.squareup.picasso.Utils$PicassoThread.run(Utils.java:354)
2020-09-28 14:59:01.895 14884-14884/com.aapmobileedb E/InstructionTarget: com.squareup.picasso.NetworkRequestHandler$ResponseException: HTTP 403
        at com.squareup.picasso.NetworkRequestHandler.load(NetworkRequestHandler.java:51)
        at com.squareup.picasso.BitmapHunter.hunt(BitmapHunter.java:219)
        at com.squareup.picasso.BitmapHunter.run(BitmapHunter.java:175)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:462)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:923)
        at com.squareup.picasso.Utils$PicassoThread.run(Utils.java:354)

Android API:
API level 29 (Android10)

Mapbox Navigation SDK version:
1.0.0-rc8

Steps to trigger behavior

1. In the examples app, choose "Navigation UI SDK" and then "Custom UI component style".
2. Long press a point on the map as a destination.
3. Observe the logs.

Start in the examples app by reproducing the Navigation UI SDK's Custom UI component style flow described in the issue, then inspect the logcat output around InstructionTarget and Picasso's NetworkRequestHandler. Determine whether the repeated HTTP 403 indicates a missing image or an expected request failure, and verify the resulting behavior against the reported logs.