After looking through the source code and the relevant changes, it seems like the way 5.5 is working now is by design? Even in 5.4, the GetValue() function for the InputAction started event would only return a non-zero value if the input’s state was set to ‘triggered’. During the started event this would already be set to ‘triggered’ in 5.4 but now the 5.5 code is forcing the started event to just be in the ‘started’ state, so any call to GetValue() returns 0 (or equivalent for vector type).
It seems like the Epic-intended way to handle getting the input value only once is to do it on the triggered event and set the triggered event to only trigger once when you want it to. Setting a “Pressed” trigger type within an InputAction will cause the triggered event to only be fired once when a button is pressed and the value from GetValue() will then be valid during that triggered event.
