Wrong "set column values" action assignment in row fields

Sounds like there’s something wrong with your setup. I would suggest using a custom form flow to do this, which is somewhat like what you have a bit different.

First up, I’m not sure why you need to send a notification (or is it just a pop up and not a push notification)?

I imagine the custom form would be built on top of a table with a single row, which contains a single column to store your sound record URL.

In your custom form, show a button to record and point it to the column above.

When the URL is not empty, show a sound player pointing to the same column. Still show the button to record in case the user wants to record again, and give them the option to clear.

Also, only when the record URL is not empty, show a button to submit it to the destination table. This would include a current date/time column, and your record URL, maybe the signed-in user’s ID/email as well.