Because of this issue https://adobe-video.uservoice.com/forums/916423-premiere-rush/suggestions/44958697-improve-media-storage-stability-in-rush-for-ios I edit with sync turned off on my iPhone. When I am back on wifi, I turn sync on.

I've noticed multiple times now that when I record voiceovers on Rush for iOS, duplicate the project to create an alternate version (eg one horizontal, one vertical), and then turn sync back on while on wifi, often times some or all of the voiceover files that were there and working fine on the iPhone prior to turning sync on will mysteriously vanish. Rush for iOS tells me it is fully synced, but on Rush for macOS it tells me it can't find the files. If I leave Rush for iOS and reopen it, it tells me that the files are not found and cannot play them back anymore.

In my usual process I do the following:

1. Create project in Rush for macOS with sync turned on.
2. Add files, let Rush for macOS create proxies and sync files.
3. Download project and files on Rush for iOS.
4. Turn project sync off on Rush for iOS.
5. Edit video, record voiceovers etc.
6. Turn sync on when editing is complete and on wifi.
7. Download changes and any new files eg voiceovers on Rush for macOS.
8. Export from Rush for macOS into relevant formats.

So somewhere in the "turn sync on" process, the files that were not already stored outside of Rush on macOS go missing. At first I wondered if it might be because I'd opened the project in macOS before iOS had completed uploading the files, but I've now experienced a couple of times where Rush for iOS simply won't upload the files and appears to be fully synced. I don't try to open it in Rush on macOS and instead close Rush for iOS, reopen it and find the voiceover files disconnected and cannot be found.

I've wasted A LOT of time with redoing voiceovers and associated editing repeatedly due to this issue.

I've noted what could be a related scenario with Premiere Rush voiceovers not appearing in Premiere Pro in the forums here: https://community.adobe.com/t5/premiere-rush-discussions/voiceover-recorded-in-rush-not-appearing-in-pro-timeline/m-p/12751096 However in this scenario they have fully synced from Rush on iOS. Nevertheless, it makes me wonder if there is some issue with how Rush for iOS handles voiceover files.