They rely on immich-go project, which is ridden with bugs and basically abandonware by now. Their own iOS app, which can also be used for syncing iCloud gallery, has outstanding, 2 y/o or so bugs that will fail to upload the Live Motion photos.
My photos exported to Immigh have some 9000 broken, half imported Live Photos and I just don't have time to fix that.
The fact that THIS is not their priority, the most comprehensively A-B tested feature is beyond me. Who cares about OCR if you can't trust that they didn't butcher your imported memories? I just don't get it!