Since you living in Canada as PR since 2003 and no travel since then, you should have been applied long before in 2006/2007. However, all you have to proof by Passport since 2003 (even expired one) that you have 1 traveled and I believe it would be fine with CIC. Also CIC will get your CBSA report where they will find the same since 2003 that will match with your passports..
However, you know Cuba is a red flag country under US eye and I am not sure how Canada sees that when a non native travels to those countries like Cuba, North Korea, Iran etc. I Hope they accept your 7 days vacation as just normal trip..
We find in this forum many applicant traveled other than their home country (US, Middle East etc) received RQ. The reason is CIC like to know more about the applicant's 3rd country visit whether they are tied with 3rd countries in terms of work/business..