Have you solved your problem? I have the same problem as you
If your tileset is similar, we discovered that there is a problem in the root tileset.json file where a geometricError isn’t specified. Make sure to add the geometric error like below (the value you use should be equal to its parent’s geometric error).
“children”: [
{
“boundingVolume”: {
“sphere”: [
4364741.3891374189406633,
511291.0278625306673348,
4608281.8367103915661573,
493.3407689303687107
]
},
“geometricError”: 493.3407689303687107,
“content”: {
“url”: “Data/Model/Model.json”
}
}
]