Yes. Origination in the Coral Triangle is well accepted. Note its location.....note the distance from it to Indonesia, to Fiji, note the difficulty coral spawn has in getting to the Caribbean....as opposed to getting to Indonesia.Also, are you suggesting that the reason that there is such thrivng biodiversity in Indonesia and less in the Carribean is becasue it all originated in Indonesia? I have not seen that as a popular hypothesis - but there are many others, for example:
What Is the Coral Triangle? | Live Science