Dynamic update billboard image - shaking

For some reason we need to generating animated billboard image base on some template.Update billboard image with generated image makes it shaking.Any thoughts?
code sample: https://sandcastle.cesium.com/#c=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

Haha I’m glad someone else has seen this. I’ve been using Cesium for years and for the first time, the other day, noticed a billboard shaking.