Sometimes jargon is like an iceberg. There is more beneath the surface than we realise. 'Let's talk offline' is one example. Superficially, this phrase means :'I don't want to talk about this in this meeting, can we talk about it later?' But it is also a historic piece of jargon which has its roots way back in the 1980s when computer technology was in its infancy, and the idea of being 'online' and 'offline' came into the collective consciousness.
Very quickly, these became symbolic terms - 'online' meaning being fashionably connected to the cyberspace and the corporate grapevine, and 'offline' translating simply as out of touch.
Dedicated students of office jargon might like to know that offline is also now synonymous with 'face time'; a period spent with fellow workers in human space/time, and 'meatspace' which means much the same thing and was first used in cyperpunk literature. Perhaps it might be better to say 'can we talk about this later?' and save everyone an awful lot of sub-text.