I have 3 relatives who spent the same couple of years out of Canada. 2 of them got called for an in-person interview...interview and oath (10 months later) went smoothly. One did not. It's most likely by random, or a program integrity check.I got the same invite for Feb 1 at the SCR office. From my reading and the helpful replies of people on this forum, I'm lead to believe that this is nothing to worry about or suggestive that there's something gravely wrong with your application. It'll likely be a 10 minute conversation, they'll ask a few questions, and it's done. LPP may complete very soon afterwards- and in some rare cases, they invite you to take your oath the very same day. I'm still apprehensive because logic dictates that I must have been selected for an interview for a reason when most people don't have to, but I'm sure it'll be just fine.
They'll just check your documents (language test, passport) and verify the info you wrote in your application, and maybe ask what you are doing presently if anything changed since your application.