You are correct. Indian English uses “doubt” to mean “question”, rather than lack of belief as is its standard English meaning. Different dialects use words differently, and there’s generally not much you can do about it. At least in this case the concepts are relatively similar, unlike by/into which normally mean multiplication/division, but are inverted in India.

exactly, it stands for "I have a question" :) It stems from the school/coaching system where you are encouraged to ask questions as you figure out say a problem set in dedicated "doubt clearing" sessions with your teachers/instructors. That carries over to the workplace where you are more likely to hear this phrase when someone has a question in a technical discussion or similar, from my observations.

This just seems like a tautology, as--from your description--it sounds like this is what I'd call a "q&a session", and so it may as well have become a "doubt clearing/solving session" because the teachers/instructors themselves also/already were taught that terminology... I'm wondering where it started, as, in English, the word "doubt" frankly almost never comes up, and if someone simply didn't learn it, they'd be fine?

You're right. "I have a doubt" means "I have a question".

We used to have "doubt-solving sessions" in coaching centres. Everytime one of the students would ask "Sir, I have a doubt" I would always snigger within that the student was insinuating something sinister or nefarious about the instructor's character. I always found it hilarious.

But that's just how English is used in India.