The OnFlowStart node and the FlowChargeUp nodes are part of a custom macro library that utilize Unreal’s latent action manager (the same mechanism behind the Delay and Retriggerable Delay nodes). These nodes are entirely independent and you can have as many as you want on one or several blueprints. For example:
I’ve talked about these nodes in detail in a previous thread which is a bit out of date:
The main tough part is creating the CustomRDelay node which is pretty much an exact copy of the Retriggerable Delay node except that it will always delay an execution pulse for at least 1 frame. Unreal did a restructuring of their C++ coding a few versions back so you may require different C++ files depending on what version you’re using. If you’re running 4.13 or below, you can use the C++ files in the above link but let me know if you’re running above that and I can try to dig up my current files. Once you have the CustomRDelay node working properly, just recreate the macros in the above link and you’re good to go.
I should mention that there are some significant bugs with these Latent State Nodes on any version before Unreal V4.19.2. If you’re running on earlier versions, then you might encounter inconsistent behavior when copying and pasting them.