Grouped media players and flows using template nodes to construct output fail beginning with 11.0.0

[grantalewis]

Describe the bug

MP3 and TTS calls sent to grouped media players and flows that construct calls using template nodes fail beginning with Node-RED 11.0.0.

To Reproduce

Additional info and example flows provided here: https://community.home-assistant.io/t/home-assistant-community-add-on-node-red/55023/1036

Expected behavior

Same behavior as in Node-RED 10.4.0.

Screenshots

No response

Example Flow

This package's version (not the Home Assistant add-on verison)

0.33.1

Is Node-RED running in Docker?

Yes

Node-RED version

1.3.5

Node.js version

14.17.1

Additional context

Apologies if any of the above-listed versions are incorrect. I am willing to attempt more accurate information if it's needed. Verified that rolling back to Node-RED 10.4.0 fixes the issue.