Have you got a source for this? On the Burgenland Croat dna project i2a is extremely low, there's dozens and dozens of r1a. And only 5 of the I2a1b they have, have DYS448=19, which is the str value associated with dinaric south, an extremely small number; the rest are din north.
https://www.familytreedna.com/public...ction=yresults
I haven't found a single person with the surname Horvat/Horvath with i2a-din south either, and I've checked many projects.