Simulcast in iOS WebRTC is sending only 1 track instead of 3

We are trying to enable Simulcast on our iOS application. Before connecting to room, we enabled simulcast, and got the following in offer payload.

a=rid:q send
a=rid:h send
a=rid:f send
a=simulcast:send q;h;f

The payload shows that 3 tracks are added in offer payload. And after that, we observed the WebRTC stat report to see the changes. However, only one frame was encoded with rid = q and sent. rid = f; and rid = h; are not encoded and sending framesEncoded=0. Here’s the log of that.

id = RTCOutboundRTPVideoStream_2851660940, type = outbound-rtp, timestamp = 1664261768776873, values = {
    bytesSent = 176170;
    codecId = "RTCCodec_0_Outbound_98";
    encoderImplementation = VideoToolbox;
    firCount = 0;
    frameHeight = 1920;
    frameWidth = 1080;
    framesEncoded = 39;
    framesPerSecond = 30;
    framesSent = 39;
    headerBytesSent = 13368;
    hugeFramesSent = 24;
    keyFramesEncoded = 2;
    kind = video;
    mediaSourceId = "RTCVideoSource_1";
    mediaType = video;
    nackCount = 0;
    packetsSent = 209;
    pliCount = 0;
    qpSum = 1546;
    qualityLimitationDurations =     {
        bandwidth = "0.54";
        cpu = 0;
        none = "1.014";
        other = 0;
    };
    qualityLimitationReason = none;
    qualityLimitationResolutionChanges = 1;
    remoteId = "RTCRemoteInboundRtpVideoStream_2851660940";
    retransmittedBytesSent = 0;
    retransmittedPacketsSent = 0;
    rid = q;
    ssrc = 2851660940;
    totalEncodeTime = "0.574";
    totalEncodedBytesTarget = 0;
    totalPacketSendDelay = "11.37";
    trackId = "RTCMediaStreamTrack_sender_1";
    transportId = "RTCTransport_0_1";
}

id = RTCOutboundRTPVideoStream_1878842665, type = outbound-rtp, timestamp = 1664261768776873, values = {
    bytesSent = 0;
    codecId = "RTCCodec_0_Outbound_98";
    encoderImplementation = VideoToolbox;
    firCount = 0;
    framesEncoded = 0;
    framesSent = 0;
    headerBytesSent = 0;
    hugeFramesSent = 0;
    keyFramesEncoded = 0;
    kind = video;
    mediaSourceId = "RTCVideoSource_1";
    mediaType = video;
    nackCount = 0;
    packetsSent = 0;
    pliCount = 0;
    qualityLimitationDurations =     {
        bandwidth = "0.54";
        cpu = 0;
        none = "1.014";
        other = 0;
    };
    qualityLimitationReason = none;
    qualityLimitationResolutionChanges = 1;
    retransmittedBytesSent = 0;
    retransmittedPacketsSent = 0;
    rid = f;
    ssrc = 1878842665;
    totalEncodeTime = 0;
    totalEncodedBytesTarget = 0;
    totalPacketSendDelay = 0;
    trackId = "RTCMediaStreamTrack_sender_1";
    transportId = "RTCTransport_0_1";
}

id = RTCOutboundRTPVideoStream_755503164, type = outbound-rtp, timestamp = 1664261768776873, values = {
    bytesSent = 0;
    codecId = "RTCCodec_0_Outbound_98";
    encoderImplementation = VideoToolbox;
    firCount = 0;
    framesEncoded = 0;
    framesSent = 0;
    headerBytesSent = 0;
    hugeFramesSent = 0;
    keyFramesEncoded = 0;
    kind = video;
    mediaSourceId = "RTCVideoSource_1";
    mediaType = video;
    nackCount = 0;
    packetsSent = 0;
    pliCount = 0;
    qualityLimitationDurations =     {
        bandwidth = "0.54";
        cpu = 0;
        none = "1.014";
        other = 0;
    };
    qualityLimitationReason = none;
    qualityLimitationResolutionChanges = 1;
    retransmittedBytesSent = 0;
    retransmittedPacketsSent = 0;
    rid = h;
    ssrc = 755503164;
    totalEncodeTime = 0;
    totalEncodedBytesTarget = 0;
    totalPacketSendDelay = 0;
    trackId = "RTCMediaStreamTrack_sender_1";
    transportId = "RTCTransport_0_1";
}

We are trying to solve this, but is not getting nowhere. We can’t seem to figure out why rid = f; and rid = h; is sending nothing. Any hint, help or any pointers are appreciated. Thanks.