Reuven's job is to check clothing for shaatnez and remove it. Shimon gives Reuven a suit to check. Later they meet in the synagogue.
Mishna Berura 151 (1) forbids even mundane talk for one's business in the synagogue.
Shimon wants to know if the shaatnez has been removed; this is not for his business – it is to avoid him doing something that is forbidden. What is involved in asking Reuven, whose business it is, if he has finished the suit? And what is involved in Reuven responding?
Let us assume that the question does not come up in the three weeks.
A shaalah has been asked of a LOR.