I don't think 'abrupt' is the right word to describe the potential issue.
Changing perspectives will be jarring if it isn't handled properly, but as long as you make it clear within the first few sentences that you have changed perspective, then I don't see that to be a problem. There are many, many books that are written from multiple perspectives.
I think what you're possibly more concerned about is that having the vast majority of your story told from one POV and then just a few random chapters or scenes from someone else might make it feel imbalanced, and I do think this is more of a possible issue.
I once read a published thriller novel by a famous author that had a single scene from an alternate POV. I did find it very jarring, but it was exacerbated by the fact the POV character was deliberately obfuscated in order to try to mislead the reader. The whole thing was badly handled, in my opinion, but I digress.
My recommendation would be to try to find ways to make your story more balanced, probably by expanding on the scenes done from the alternate POV. Could you make it so there are at least three scenes from one alternative POV? Or possibly three each from a different POV. Three is the magic number for making things feel complete...
As an aside, I definitely don't think crow-barring your main protagonist into those scenes sounds like a good idea.
Anyway, all of this is very subjective, but there's my opinion.