Error when trying to use SessionRecording with Blob

[MaorZ]

When I try to run the following line:

guacSessionRecorder = new Guacamole.SessionRecording(blob);

I get the following error:

recorder error:  TypeError: Cannot read properties of undefined (reading 'size')
    at readNextBlock (guacamole-common.js:12751:1)
    at parseBlob (guacamole-common.js:12767:1)
    at new SessionRecording (guacamole-common.js:12873:1)

After insvestigating the Source code I stubleed upon this code in the SessionRecording.js file (Line 401-402):
Here

if (source instanceof Blob)
  parseBlob(recordingBlob, loadInstruction, notifyLoaded);

But you can see it doesn't use the blob as a sorce but rather using the empty recordingBlob variable

After investigating the other port repo name guacomole-client (same file in line 469):
Here

if (source instanceof Blob) {
    recordingBlob = source;
    parseBlob(recordingBlob, loadInstruction, notifyLoaded);
}

It seems that some logical error or missforking the actual apache code

Pleas advice