The bug is actually caused by a flag that Google recommended to be turned on for a better security against CPU Speculative Execution Attack Methods (Spectre). According to the Comodo Browser Team, you can turn this issue off by writing into a new tab of Comodo Dragon the webpage: chrome://flags, after this, search for the "Turn Off Strict Site Isolation Feature" and click on Enable and then restart the browser. After that games should work as before in Facebook. PLEASE SHARE.
***DISCLOSURE: Please Note that the Strict Isolation Feature is a SECURITY tool that helps prevent hackers access to your login credentials. Site Isolation protects your browser against ransomware and other malware, and also control Spectre processor security vulnerabilities. So make sure you read this information BEFORE you disable this feature.