WMTS layer does not load at certain zoom levels

[sjpinizzotto]

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Description

Worldwind is not loading tile sets above certain zoom levels for some WMTS. The WMTS service loads onto the map. Zooming in past a certain level the service disappears and new WMTS service requests are not made.

Steps to Reproduce

1. Load WMTS service https://services.arcgisonline.com/arcgis/rest/services/World_Imagery/MapServer/WMTS

2. Use either default028mm or GoogleMapsCompatible tile matrix sets. World_Imagery should be the layer. Using default028mm an exception is generated, but GoogleMapsCompatible tile set does not generate exception.

3. Zoom in on united states (the error is only occurring here -- seems as though europe works) . For deafult028mm, the map will only zoom to level 9, GoogleMapCompatible went a little lower, but only to 12.

Expected behavior: [What you expect to happen]
Entire WMTS service tile sets should be viewable. Verified on other map engines that service works.

Actual behavior: [What actually happens]
WMTS service stops being requested at a specific zoom level

Reproduces how often: [What percentage of the time does it reproduce?]
Reproducable all the time.

Operating System and Version

Mac OS High Sierra 10.13.6

Additional Information