1. Build a mission with two units in it. Name them Carl and Ermy.
2. create sentenceDB.bikb in the mission's root:

class Sentences
{
    class ErmyHelpPlane
    {
        text = "";
        speech[] = {"sound\ErmyHelpPlane.ogg"};
        variant = "";
        variantText = "";
        class Arguments {};
    };
   class Carl1B
    {
        text = "";
        speech[] = {"sound\Carl1B.ogg"};
        variant = "";
        variantText = "";
        class Arguments {};
    };
};

3. Make some voice recordings. Name them Carl1B.ogg and ErmyHelpPlane.ogg. Create a folder in the mission root named sound and drop them in there.
4. Create .lip file for each
5. Run the mission on a dedicated server and join up.
6. Run the following code in the debug console on the server:

Ermy linkItem "ItemRadio";
Carl linkItem "ItemRadio";

Ermy kbAddTopic ["test1Topic", "sentenceDB.bikb", "", ""];
Carl kbAddTopic ["test2Topic", "sentenceDB.bikb", "", ""];
[] spawn {Carl kbTell [Carl, "test2Topic", "Carl1B", ["",{},"",[""]], false]; sleep 0.5;Ermy kbTell [Ermy, "test1Topic", "ErmyHelpPlane", ["",{},"",[""]], false];};

PLEASE CHECK THIS VIDEO OF THE BUG: https://youtu.be/sdLyEm3NNRM

Directions for Repro Mission: Run the mission on a dedicated server and join (mission is done quickly with only one player in mind). Use your radio menu (press 0, by default), and use 1 to make Ted Talk, 2 to make Bill talk, and 3 to make them attempt to talk at the same time, reproducing the bug.

Repro Mission: