Hi,
Would it be possible to elaborate a bit on what specific event behavior you are aiming to achieve? Could I get a screenshot of how you set up the event in FMOD Studio?
You could use Transition regions and conditions (FMOD Studio | 27. Glossary | 27.170 Transition Region) to smoothly switch sound.
Alternatively, you could have a look at a similar post here, for which I will share it here: Sound plays double
Hope it helps, let me know if you have any questions.