Random upload failures only on IPv6 connection

I’ve been noticing strange upload failures when syncing large video exports download from here. The issue only seems to happen on IPv6-enabled networks — uploads either stall midway or fail without a proper error message.

Switching to IPv4 temporarily fixes it, which makes me think this could be routing, MTU, or CDN-related rather than an application bug itself.

Has anyone else seen unstable media uploads specifically over IPv6 recently?