ffmpeg problem video duration of an hour and a half

When start record i call an api /start-record which does:

const ffmpeg = spawn("ffmpeg", [
        "-i",
        rtsp,
        "-c:v",
        "copy",
        "-an",
        "-f",
        "flv",
        `${filename}.flv`,
      ]);
ffmpegProcesses[rtsp] = {
        process: ffmpeg,
        filename,
      };

When stop the record i call an api /stop-record which does:

ffmpegProcesses[rtsp].process.kill("SIGKILL");
ffmpegProcesses[rtsp].process.on("exit", async () => {
   const ffmpeg = spawn("ffmpeg", [
          "-i",
          `${filename}.flv`,
          "-c:v",
          "libx264",
          "-preset",
          "fast",
          "-crf",
          "30",
          "-an",
          `${filename}.mp4`,
        ]);

    ffmpeg.on("exit", async () => {
        uploadToS3()
    })

})

If the recording is less than or equal to approximately 1 hour it works perfectly, but if the recording is 1 and a half hours it already breaks and it does not correctly generate the files, nor the flv nor the conversion to mp4

I hope my program works the same way it does for 1 hour recordings