Contract signed initially says 2 years, before going to place of assignment,contract changed to 2.5 years

I came fr the Philippines, initially i signed a contract for 2 years then before leaving the country, it was changed to 2.5 years and they let us sign it.

Do you think it is fraudulent since they let us sign the contract 6 months before I leave the country? And another amendment was done a week before leaving the country.