1. Issues of instability or corruption
Not every property investment overseas is going to be plagued by corruption, require bribes, involve unlicensed real estate sales, etc. Most mature states, like Japan or the UK, have well-enforced laws. Perhaps a useful reference here is the Corruption Perceptions Index, which is updated annually.
A loose rule of thumb is to stick to countries within the top half of the list (e.g., only countries that rank 89 or above), although some investors may have more stringent standards*.
As with buying property in Singapore, you can scrutinise the development team as an added safety measure. It’s a fairly safe bet that proven international developers, like Australia-based Lendlease, or the UK-based Berkeley Group, would not attempt to build properties in corrupt or unstable states. Some of these large developers have local projects that you can visit (Lendlease, for instance, is behind the development of Paya Lebar Quarter).