not weird at all imo. especially if they're of a younger age and therefore more flippant with endearments. it's not suppose to be taken seriously anyway. i see this regularly on various social media such as twitter, tumblr, etc.

But the social media sites are a different kettle of fish...they are hardly a business environment where you would expect people to be more formal in their communication.

As for younger people being more flippant...they could do well to realise that they may be dealing with someone of the older generation who expects and appreciates a bit of formality in business dealings.