Is it weird to eat alone at the office? Genuinely asking

I like eating alone. Not because I dislike my colleagues — I genuinely like most of them. But lunch is one of the few times I get mental space in a loud open-plan office.

I've noticed that eating alone is sometimes read as antisocial or as a signal that something is wrong. A few people have asked if I'm okay when they see me with headphones and a book at the mamak downstairs.

Is this a Malaysian office culture thing specifically? In what contexts is solo lunch totally normal and in what contexts does it create an impression you'd rather not give?

Also curious: how do people handle the "want to join us for lunch?" question when you really just want to be alone without it being a whole thing.