I'm currently using Fluconazole as well.
I started with Vibrant about 4 weeks ago due to a GHA outbreak that I could not get under control through normal measures (it also takes a really long time to die with a blackout - my sump rock was completely carpetted with it and it stayed alive for weeks after pulling the fuge light. only died due to vibrant)
I just recently added in fluconazole because I noticed tiny patches of bryopsis starting up and these things are always best treated immediately if possible.
As far as corals go, I have had some losses due to botched H2O2 treatment where I got carried away blasting multiple areas of the tank and realized I had put way too much peroxide in after I was done. This predated my vibrant / fluconazole treatment. Lost a chalice and several heads of candy cane coral, as well as half of a cyphastrea plug before stabilized.
Since then I've lost a yellow fungia plate for unknown reasons - probably irritated too often with sand from a hectors & links goby.
I don't believe any of these losses are due to vibrant OR fluconazole. SPS (monti, acro, birds nest, etc), LPS (hammer etc) are all happy. I just mention it for transparency.