To my ability, I did not recognize any fighting (I did witness a bee last year fighting a wasp/yellow jacket while I was feeding in late summer).
High traffic did not look like fighting. It looked at lot more like "bearding", but last summer, usually both hives bearded when they did, so it looked surprising that only one did this time.
Moreover, the non-traffic hive, has only one bottom entrance with solid bottom and non-ventilated inner cover, while the high traffic one, has two entrances (bottom and top) with a screened bottom board and ventilated inner cover, so if I was to see any bearding behavior, I was expecting to see it on the non-traffic hive -- yet the bees surprised me yet again.