Chances are high since you had two previous approvals. No, you don't need to explain why you didn't travel the second time. Presumably this was due to COVID which would have happened to a lot of people. If it makes you feel better, you can certainly include an LOE.
Looks like you may have been interested in applying for PR? Did you ever apply? The fact that you were only granted a 6 month visa and then a 3 year visa means there was concern about your application. May be due to what country you are from. The fact that you did enter Canada and left makes your application stronger but you were only given a 3 year visa for your second visa so there does remain some concern about your application.
Looks like you may have been interested in applying for PR? Did you ever apply? The fact that you were only granted a 6 month visa and then a 3 year visa means there was concern about your application. May be due to what country you are from. The fact that you did enter Canada and left makes your application stronger but you were only given a 3 year visa for your second visa so there does remain some concern about your application.
