Why do locals in Kolkata and Dhaka respond differently when I use the 'tumi' vs 'apni' verb endings?

I’m an intermediate learner and I keep getting confused by the honorific levels. I feel like whenever I try to apply what I learned about 'apni' from textbooks, native speakers in Bangladesh seem slightly put off or amused, while my friends in West Bengal seem to expect it. How can I navigate these regional differences in verb conjugation without sounding like a robot or accidentally being rude? I am asking specifically about learning Bengali, not a generic study routine.