Audio being removed from shared, edited videos

Not long ago, I needed to remove the audio from a video on my iPhone before sharing it. I searched and discovered it is surprisingly easy: just edit the video, click the sound/volume icon at the top left, save, and the audio is gone. But, ever since then, the sound is removed from all my edited videos, on both my iPhone and iPad, when I share them. When I edit the video, the sound/volume icon at top left still indicates audio exists, and audio is present in the edited, saved video in the Photos app on either my iPhone or iPad, but recipients of the shared, edited video (both when it is sent by text, or posted to Facebook) don't receive any audio. This was never a problem before I removed the audio from the video I needed to share without audio.

How do I go back to being able to share edited videos with recipients still receiving audio?