Blueprints events send values only on second trigger

i have a custom event that sets an object (waveasset) and then plays the metasound.
the result is metasound is playing with its default waveasset.
on the second trigger of the event it is taking my blueprint set asset and plays it correct.

this behaviour is happening for me with all events no matter what parameter i set via parameter interface.

is this a known issue? do i do something wrong?