Valve are now stopping users from gifting Steam games that are bought cheap in one country to friends or users in another country. This currently doesn't seem to affect those in North America, Europe or countries where prices are typically higher.
The current pricing method for Steam games across regions is based on a conversion rate and the typical price of comparable products in the market. The change has come about since the collapse of the Russian ruble, following their annexation of Crimea earlier this year. The change prevents Russians from buying the games incredibly cheap and selling them on for a much higher rate to those in other countries.
If you want to know what countries are region locked from gifting then reddit users have compiled a list, which shows a list of confirmed countries, mainly those in Asia, South America and Eastern Europe.
The change comes ahead of the star to the holiday sale which is due to kick off at 10am PST today, so stay tuned for that!