Specifying a list of Playsources to the PlayToAll method generates ERROR Status code 400, "{"error":{"code":"8523","message":"Invalid Request, more than one play source detected."}}"]

[JohnMelody]

SDK: azure-communication-callautomation V1.1.0

I have set up a list of play sources as follows:

List<PlaySource> lPlaySourceList = new ArrayList<PlaySource>();

Then I created a list of audio files to play

"prompt1.wav;prompt2.wav;prompt3.wav"

Then build an array list of prompts to play using the audio files.

List<String> lPromptList = Arrays.asList(lPrompts.split(";",-1)); lPromptList.forEach((s) -> { log.info(s); PlaySource lPlaySource = new FileSource().setUrl(mAppConfig.getBasecallbackuri() + "/folder-name/" + s + ".wav"); lPlaySourceList.add(lPlaySource); }); log.info("Number of PlaySources = " + lPlaySourceList.size());

then I try to play them with the following

mClient.getCallConnectionAsync(callConnectionId) .getCallMediaAsync().playToAll(lPlaySourceList).block();

However, I get the following error:
com.azure.communication.callautomation.implementation.models.CommunicationErrorResponseException: Status code 400, "{"error":{"code":"8523","message":"Invalid Request, more than one play source detected."}}"

Why is it an invalid request? Yes, there are more than one playsource but that's what the API call expects i.e. a List of PlaySources.

What am I doing wrong? My "PlaySource"s are "FileSource"s.