"Unfortunately what we're finding in the last year is all our key buying powers, whether they come from Argentina, Venezuela, Colombia, Brazil, Russia, all their currencies are falling against the dollar. So suddenly the foreign buyer who saved us the last go around are still present, but they're not as prevalent as they had been," said Peter Zalewski, founder of Condo Vultures, a Florida real estate consultancy and analytics firm.
Miami went from boom to bust to a relatively quick recovery, thanks to the power of international cash. Amid a stronger dollar and weakening foreign currencies, that buying power is not nearly as strong today.
Read More Miami amusement tower's ticket to US citizenship
And yet construction surges ahead: 325 new towers are proposed in South Florida, with just more than 41,200 units, according to Zalewski. Of that, roughly 13,000 are in the planning stage, another 15,000 are approved and trying to sell, and the remaining 13,000 to 14,000 are under construction or recently completed.
There is still strong demand in Miami, especially among Latin Americans who increasingly fear the political situations in their countries. They need to park their money somewhere, and Miami is the logical place, given the diverse culture and Latin American influence already there.
There is also big interest from Russians and Chinese as well as Canadian buyers, but now they are looking a little bit lower on the price ladder.
"Those four-bedroom, $4 million condos don't necessarily look as attractive as a studio apartment that maybe will sell for somewhere in the vicinity of $300,000," said Zalewski.
Read MoreDemand for government-backed FHA loans spikes
That puts the luxury Miami market at risk yet again. Not the case back on Fisher Island, though, where the sheer exclusivity makes it an island unto itself in every way. Now, with two new ultra-luxury towers, values across the island are rising again. Any issues with foreign currency appear not to have crossed the water yet.
"Maybe we're on jet lag," added Puig, "but we're not feeling it."