VRCSDK3-UDON-2020.04.25.13.00 became unable to handle joining flow control. Previous VRCSDK3-UDON-2020.04.17.11.43 works fine.
1st image is VRCSDK3-UDON-2020.04.25.13.00. 2nd is VRCSDK3-UDON-2020.04.17.11.43. Different assembly is generated and new SDK result is wrong.
This is fixed in the next release.
This issue also happened with Branch node. It seems that the assembly generator just ignores a flow which is connected to previously visited node.