ClubMan said:
I can only speak from personal experience with regard to travel and not investing which could be different. I have been to Cuba 3 times and have probably been through the US over 10 times since the first trip and have never had a problem.
I think the main issues with Cuba are actually more related to the embargo than its status on the list of sponsors of terrorism and apply more so to US citizens and residents (such as green card holders).
The one area where the US does seem to try to apply sanctions against non US residents is on technology transfers to these countries (I seem to remember Aer Lingus facing issues over selling parts to Iran?) but I have never heard of it for purchasing property other than private civil actions such as the exiles bring (though that is far from definitive).