Bug with getAccessKey in ModelAnimationCache

getAccessorKey is using buffer.path from the gltf, but buffer has “uri” property.

Came across this when I add multiple animations that are ran separately. When they animations had the same number of frames, the cache key would collide between the accessors.

Thanks for the report, I opened a pull request here: https://github.com/AnalyticalGraphicsInc/cesium/pull/5064

Jason, thanks again for the report, #5064 was merged and will be in the Cesium 1.32 release on April 3.