what does passing means here?
The main issue we were facing was the unresolved defects affecting Crum's clients. I can also mention the other tech issues in passing

thanks!Can "the main problem" be substitued by "the main setback?

Question

what does passing means here?
The main issue we were facing was the unresolved defects affecting Crum's clients. I can also mention the other tech issues in passing

thanks!Can "the main problem" be substitued by "the main setback?

Answer

Mentioning something 'in passing' means mentioning it alongside the main topic of conversation. It will be something insufficiently important to mention by itself, but while you are discussing a related topic it is little trouble to mention it as well.

Answer

I agree with Jimmy, however; I would like to mention that talking to someone in passing refers also to "small talk" details that would be trivial: not of dire importance unless "need-to-know basis" such as an investigation or really nosy person.

Answer

DOES+VERB+S (WRONG) DOES+VERB(CORRECT)==== WHAT DOES PASSING MEAN HERE