I have an express entry profile created on January 2018. Then I applied for TRV 1 month ago and got refused.
Now there is a section in express entry online application called "Immigration history and citizenships" with a question "Has X applied to Immigration, Refugees and Citizenship Canada before?". The answer for that was "No" when I first created the application.
Now do I need to update this answer to "Yes" after I applied to TRV and specify the UCI given in TRV ? Note that Express Entry application already have another UCI set.
The UCI will be eventually synced to your UCI (the one from the TRV application), this may be done automatically after ITA.
But yes, it is the applicants obligation to keep the profile up to date, so you need to update the answer.
Don't worry, a simple TRV refusal doesn't affect your PR application as long as you are truthful about it and disclose it when asked in the forms.