Suddently, compile errors because multiple definitions of interrupts. (Jack_M)

I am updating a working project.I modified one source/header module and now i can't compile during linking, the error i get isbuild/default/production/interrupts.o(.isr.text+0x0): In function `_T1Interrupt':
C:\Lavoro\HARDWARE\350.950\FIRMWARE\350.95..