This question already has an answer here:
Working in international groups where different participants communicate through a common language, often English, can lead to unintentional innuendo. In this case the innuendo is due to slang terms in a different culture than the speaker's own. The difference to other questions of a similar nature is that the speaker has no malevolent intents, direct or in-direct, but is ignorant of another culture's colloquial expressions.
When speaking with some German colleagues the other day, the project leader uttered:
Ah, it is good to see that you are hard on the lube.
Where I am from this is often used as a slang term for rough sex or used to imply that someone is a sexual deviant. Now I know the fellow and he is ignorant to the connotation of the phrase. In German, I believe, there is a similar phrase using the word grease which changes the context and is intended as something positive.
Following some comments from German speakers it would seem that being hard on the lube is not a wrongly translated phrase from German. It could be internal jargon or the PL simply wanted to express gratitude for a job well done but chose poorly when translating.
I politely informed him that the phrase might be interpreted as something sexually and negative, he laughed it off and we continued the meeting. Afterwards I received an email from the PL's superior who chided me for correcting him in front of the rest of the group. He also CC:ed my superior in my home office.
As user Draken has already pointed out it would have been better to have made these comments in private, allowing the PL to save face in front of the group. We have been working together for the past year and direct feedback was encouraged in the group. I assumed that an innocent comment meant in good spirit would be seen as no harm, no foul, I stand corrected. I contacted the PL afterwards to apologize and he has made no formal complaint and said to me directly that he didn't take offence.