I agreed with Jacky and Hero Lung. Stress not only come from his work but also other external causes such as the mistrust relationship Bruce had with Raymond Chow and people around him, the feuds with the HK Martial Arts Community, the bad relationship with the newspapers who intruded his family privacy and the triad society trying to get a share from him etc.
Having a break after ETD didn't mean he wasn't having much stress. If Hong Kong was such a great place with little stress especially during the last few months of his life, he won't be wanting so much to leave for the U.S.
Really makes no sense at all.
Keep in mind the July 5th Lo Wei's incident followed by clashes with an editor at Raymond Chow office and Jackie Chan's bowling account a week before his death etc. Witnesses like his butler Wu Ngan, the above editor, Jackie Chan and some other stuntmen all claimed that Bruce looked either stressed up or troubled in the last month of his life. These guys couldn't be lying and saying similar things about Bruce.