Is it normal my boyfriend followed his friend’s girlfriend on IG?

and it makes me uncomfortable. Especially how he kinda brushed it off like normal things when clearly didn’t it sit right with me seeing some random girl following him and then noticing he followed her back a few days later. Just when I believe we have something solid, something aligned and pure and honest. I never met these people, but I feel so outside of it because of our LDR. I feel like I am kept apart. I just wished he was more transparent, he knows these things bother me and one of the things that were a green flag to me was the fact he wasn’t paying so much attention to social media. To me, it’s a breach of personal boundaries.
Is it normal my boyfriend followed his friend’s girlfriend on IG?
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