Error Transcoding DJI H.264 to ProRes - Media Offline

Native footage is

H.264 (.mov)
DJI Phantom 3 Pro, Phantom 4 Pro
3840x2160

I'm trying to edit an aerial reel inside of Resolve. Made the mistake of trying to work natively with the .264 footage and playback/scrubbing got choppy pretty quick. Optimizing media and viewing proxy mode didn't help so I decided to transcode. Set my transcode to ProRes422HQ 1920x1080 and about 95% of the clips were successfully created. The remaining new clip files were created but show as "Media Offline." The offline clips are visible in the new folder I created so the files are there. When I scrub through the "offline" clip there are brief portions of the clip that were transcoded, but the red "Media Offline" icon is present most of the time. Tried transcoding at the native resolution and that was even less successful as the entire new clip was "Media Offline."

Any help would be appreciated!