I use a mac, too, and for the last week or so, EVERY attempt to access the Black Lion Trading company has blanked out, completely, or not fully loaded, with the exception of the coin collection option.
Gem store, Currency exchange, Trading company, placing item onto trading company, listed items, none of the tabs (except for the “Pick up” tab) have loaded for me.
I’d thought perhaps after this update it would be fixed, as it seemed to coincide with the preparation for this latest patch, but apparently not.