I managed to catch this, extracted from https://api.tfl.gov.uk/Vehicle/LTZ1179/Arrivals which possibly explains why I’m not seeing predictions for most of the stops

There are some inbound predictions, but there should be one for every stop.
Here’s an example of the response for that vehicle (though not taken at exactly the same time as the above:
[
{
"$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
"id": "209001210",
"operationType": 1,
"vehicleId": "LTZ1179",
"naptanId": "490004172S",
"stationName": "Botany Bay / the Robin Hood",
"lineId": "313",
"lineName": "313",
"platformName": "null",
"direction": "inbound",
"bearing": "125",
"destinationNaptanId": "",
"destinationName": "Chingford Station",
"timestamp": "2023-09-08T07:22:28.2241991Z",
"timeToStation": 98,
"currentLocation": "",
"towards": "Enfield Town",
"expectedArrival": "2023-09-08T07:24:06Z",
"timeToLive": "2023-09-08T07:24:36Z",
"modeName": "bus",
"timing": {
"$type": "Tfl.Api.Presentation.Entities.PredictionTiming, Tfl.Api.Presentation.Entities",
"countdownServerAdjustment": "-00:00:05.9873940",
"source": "2023-09-08T02:15:07.102Z",
"insert": "2023-09-08T07:22:06.437Z",
"read": "2023-09-08T07:22:00.435Z",
"sent": "2023-09-08T07:22:28Z",
"received": "0001-01-01T00:00:00Z"
}
},
{
"$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
"id": "-170886920",
"operationType": 1,
"vehicleId": "LTZ1179",
"naptanId": "49003148B",
"stationName": "Chase Farm Hospital / the Ridgeway",
"lineId": "313",
"lineName": "313",
"platformName": "B",
"direction": "inbound",
"bearing": "147",
"destinationNaptanId": "",
"destinationName": "Chingford Station",
"timestamp": "2023-09-08T07:22:28.2241991Z",
"timeToStation": 468,
"currentLocation": "",
"towards": "Enfield Town",
"expectedArrival": "2023-09-08T07:30:16Z",
"timeToLive": "2023-09-08T07:30:46Z",
"modeName": "bus",
"timing": {
"$type": "Tfl.Api.Presentation.Entities.PredictionTiming, Tfl.Api.Presentation.Entities",
"countdownServerAdjustment": "-00:00:05.9873940",
"source": "2023-09-08T02:15:07.102Z",
"insert": "2023-09-08T07:22:16.461Z",
"read": "2023-09-08T07:22:10.44Z",
"sent": "2023-09-08T07:22:28Z",
"received": "0001-01-01T00:00:00Z"
}
},
{
"$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
"id": "386714771",
"operationType": 1,
"vehicleId": "LTZ1179",
"naptanId": "490006587E",
"stationName": "Enfield Town / Church Street",
"lineId": "313",
"lineName": "313",
"platformName": "E",
"direction": "inbound",
"bearing": "92",
"destinationNaptanId": "",
"destinationName": "Chingford Station",
"timestamp": "2023-09-08T07:22:28.2241991Z",
"timeToStation": 983,
"currentLocation": "",
"towards": "Ponders End",
"expectedArrival": "2023-09-08T07:38:51Z",
"timeToLive": "2023-09-08T07:39:21Z",
"modeName": "bus",
"timing": {
"$type": "Tfl.Api.Presentation.Entities.PredictionTiming, Tfl.Api.Presentation.Entities",
"countdownServerAdjustment": "-00:00:05.9807888",
"source": "2023-09-08T02:15:07.102Z",
"insert": "2023-09-08T07:22:06.437Z",
"read": "2023-09-08T07:22:00.435Z",
"sent": "2023-09-08T07:22:28Z",
"received": "0001-01-01T00:00:00Z"
}
},
{
"$type": "Tfl.Api.Presentation.Entities.Prediction, Tfl.Api.Presentation.Entities",
"id": "-587481917",
"operationType": 1,
"vehicleId": "LTZ1179",
"naptanId": "490007258P",
"stationName": "Glyn Road",
"lineId": "313",
"lineName": "313",
"platformName": "P",
"direction": "inbound",
"bearing": "97",
"destinationNaptanId": "",
"destinationName": "Chingford Station",
"timestamp": "2023-09-08T07:22:28.2241991Z",
"timeToStation": 1710,
"currentLocation": "",
"towards": "Chingford, Bush Hill Park Or Edmonton",
"expectedArrival": "2023-09-08T07:50:58Z",
"timeToLive": "2023-09-08T07:51:28Z",
"modeName": "bus",
"timing": {
"$type": "Tfl.Api.Presentation.Entities.PredictionTiming, Tfl.Api.Presentation.Entities",
"countdownServerAdjustment": "-00:00:05.9873940",
"source": "2023-09-08T02:15:07.102Z",
"insert": "2023-09-08T07:22:16.461Z",
"read": "2023-09-08T07:22:10.44Z",
"sent": "2023-09-08T07:22:28Z",
"received": "0001-01-01T00:00:00Z"
}
}
]