Builds occasionally disappear across entire hero pool

[Tianes]

This one's a little more difficult to provide extra info on, but it feels like once every month or so, all of my saved builds for a hero, local and favourited, completely disappear, needing to have me re-make them if they're bespoke, which is very frustrating
When this happens it seems to occur across the entire hero pool, so everyone has their saved builds completely reset