Question: Say you are working in an office where English is not a native language for people but some English terms are used very often (e.g. an IT department). And your boss always pronounces English terms incorrectly.

The question. Is it appropriate to pronounce the terms correctly when speaking to the boss or one should use his wrong pronunciation for any reasons.

It seems to me a bit uncomfortable to use the fixed pronunciation just after his incorrect wording (right in the next sentence). He may find this offensive I think. He may think that I'm either too dumb to remember how it's pronounced after one second after his saying or I'm trying to teach him.

P.S. Trying to tell him how it's pronounced correctly is not an option. Please avoid this advice. Thank you.

Answer: 
As long as you are not gratuitously using the words, you should always aim at correct pronunciation. Knowingly imitating an incorrect pronunciation is dishonorable and groveling behavior. Correct behavior is to pronounce words correctly and ignore other people who may be pronouncing the word incorrectly.

The only thing to avoid would be unnecessarily using a word you know to be pronounced incorrectly by someone else. Repeatedly or unnecessarily speaking such a word could be construed as an attempt to humiliate the other person. Therefore, you should only use the word when absolutely necessary and avoid using such a word needlessly.
It's less important how he pronounces it then it is that you understand him. Lots of people have lots of different accents. There is no reason I can think of for a person to mispronounce on purpose.

So I would just pronounce the word/s correctly as I know them. I live in a country where my accent is very different, over time my accent has changed a bit, but it wasn't a conscious change, just the natural one that comes from your environment. In any case it has never really impacted on my ability to communicate in English which is the norm for technical discussions.

If I tried to imitate their accents when talking to them, they would probably think I'm trying to be funny. As far as which pronunciation is correct, mine is in most places. But in their country theirs is, so it's relative to the situation. The important thing is we're mutually intelligible. The native language here does not have all the same sounds as English, so for them to pronounce my way would be very difficult for some. Much as I will always speak their language with an accent.