When there are two 264 fields with blank indicators, Koha seems to display the second 264 field display rather than the first 264 field.
Created attachment 38885 [details] normal display in staff
Created attachment 38886 [details] marc display in staff
I believe this is not a bug per se, but Koha trying to make a good guess on which entry being the best one to display in absence of the indicators. Also the screenshots prove that indeed the first one IS displayed. I am closing this as WORKSFORME, but please feel free to reopen.