Strange error message when compiling an IPA ("multiple L$start$ labels found at same address in...")

I get this message when compiling an IPA with AIR 3.6:

ld: warning: multiple L$start$ labels found at same address in __ZN9NetStream12DispatchProcEP10NativeInfo at offset 0x06C0

Googling a bit, it seems it's an error message from this C++ class:

http://opensource.apple.com/source/ld64/ld64-133.3/src/ld/LinkEdit.hpp

So I suppose it's a bug in the AIR for iOS compiler. Any clues about why am I getting that warning message?