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.
I'm going to answer this question as the person who mispronounces words. I'm a native English speaker but have started picking up French late in life. I can follow a conversation and speak short sentences. I slaughter the pronunciation of words; a native or fluent speaker can understand me though.

I personally prefer if native French speakers use proper pronunciation around me. **Foremost because I couldn't understand them if they used my own mispronunciation.** A secondary reason is maybe, through some odd osmosis or asking outright, I'll pick up the correct pronunciation over time.