Bad place to pick up frags, IMO. Moved into newly set up temporary tanks of "foreign" water, moved again on your purchase, not the best thing for corals by far. The simple act of acclimating rapidly can cause bleaching, along with a host of other causes, light change (new corals should be kept darker at first), high temperature, pollution (nitrogenous nutrients, et. al.), proximity to competing corals (chemical probably), etc.