Hey @Magoo7 !
I had the same problem, and I also have been trying everything to fix it (started at 11:40pm thinking it would be an easy thing to fix but now is 3:12am 
)
I’m glad to tell you I found a workaround! For now, I’ll call it a workaround because the old way should be able to work unless I may be misunderstanding how the audio system works, which could be possible because I haven’t researched it as much as I would like.
The same issue is affecting my Stepping sounds for surfaces. When I set the Integer parameter in my soundcue to ‘Swimming sound’, it won’t switch back when I walk on the ground again.
So the code that used to work for me is this one. Which played different footstep sounds depending on the surface. That FootstepComponentRef is an Audio Component inside my character, where I can change that Integer value to update the type of sound that should be played
Looking around the audio component inside my character, I found this little category, that I don’t remember if I saw it before or not, called Default Parameter. I didn’t know if it worked correctly, so to test it I added my parameter name and value and decided to disconnect all the code the changed the parameter value.
This little change seemed to work, and if I manually changed the value before playing in the editor, the sound seemed to change.
Now, thinking logically, if it’s an array I can probably change the value in runtime and maybe UE5 will like this new approach, so I changed my previous code to this:
And this way of changing the value worked!
Hopefully I managed to explain myself well before passing out, but do let me know if this worked for you or if you found another solution.
Kind regards,
Ram