VRCSDK-2019.08.23.13.45 upon after building removes all dynamic prefabs. See video:
Fixed in a previous update.
On going open beta SDK VRCSDK-2019.09.09.18.43 fixes this issue. (Download link is on the last "Updated: 17 September 2019 " message of official Discord open-beta-info channel. Be careful it isn't open-beta-notifications) Cited from release note draft ( https://docs.vrchat.com/v2019.3.2/docs/latest-release ) : "Fixed an issue where user-defined dynamic prefabs would be wiped from the VRC_SceneDescriptor during scene building"
same issue, my Dynamic prefab automatic remove all the list
Was meant to be posted under SDK Bug reports.