Created attachment 467826 [details]
Sample html/javascript to replicate issue

When using MediaRecorder with a specified timeslice property, ondataavailable keeps getting called on every timeslice event, regardless if MediaRecorder has been paused. Have replicated this occurring on Safari for iOS 16 + 17 as well as on macOS Ventura 13.5.2 Safari version 16.6.

Issue:
The attached example has a timeslice of 5000 that is supplied on mediaRecorder.start(5000). When recording is started the mediaRecorder.ondataavailable event will fire every 5 seconds. Upon calling mediaRecorder.pause(), mediaRecorder.onpause event fires and mediaRecorder.requestData() is called which should result in mediaRecorder.ondataavailable triggering one more time and then stop/pause (this is the current behavior with other browsers). Safari iOS 16 + 17 continues to call mediaRecorder.ondataavailable at every timeslice event with the same blob even though mediaRecorder.pause() was called.

Expected behavior:
Upon calling mediaRecorder.pause(), mediaRecorder.ondataavailable should not continue to fire continuously.

Replicating:
1. Launch index.html from attached zip
2. Tap the Record button
3. Record several seconds then tap the Pause button.
4. mediaRecorder.ondataavailable will continue to be called every 5 seconds. Added a debug div that will show the consolelog output on the screen and you'll notice ondataavailable... continue to get outputed every 5 seconds.