It is cultural - the whole "not losing face" thing. In a project, I once was squad lead - I was onsite, my squad members were in Bangalore of course. Same experience as you. Once I wanted to talk about a piece of code that we need to improve and refactor, and I was acting in good faith calling the dev that commited that code. When I braught up the code on my screen to start a pair programming, he immediately denied having written the code. Unfortunately for him, being a junior, he did not know about git blame - I entered it in the terminal and his name showed up on that code. Still, he would simply just deny that he wrote it. I then took the git commit hash and looked it up in gitlab, able to bring up the MR he created and the reviewer (wasn't me). Even with that on screen, he still denied being the author - with no arguments or alternative reasoning, he just constantly would repeat "No, I haven't written that". "No no, but I haven't written it". I pulled even the JIRA ticket up, that was about that feature and guess what - he was the assigne and moved it to "In Progress" and "Done". Still with that on screen all I got was a "no, haven't written it".
I had more of those interactions, and we also exchanged some of the indian devs (they were sold to the client by a big consulting group, and immediately replaced by someone else if we wished). I later found out, people that I have had replaced in my sqaud for not being qualified, ended up in different teams in the same corporation, they were basically just moving around inhouse.
After a few month in the project I swore to myself never to work with offshores again. And as a side note, the bank I did the project with, does not exist anymore :)