Hi Niall
I have seen this behaviour too. From what I can see the adapt_contrib_narrative.js is mis-reading the following line:
var slideWidth = this.$('.narrative-slide-container').width();
It's picking up the width from the narrative.less, however it's ignoring the % sign and setting the images to be 60 pixels wide instead of 60% wide. I've tried to force this to 60% wide, but when I do all of the images are displayed vertically in the first narrative image window. What's odd is that when trickle triggers, this line in the adapt_contrib_trickle.js:
Adapt.trigger('device:screenSize', Adapt.device.screenWidth);
(which is part of onTrickleButtonClicked: function(event) ) resizes the images and the narrative displays properly.
I haven't found a fix for this yet.
Have you had any further luck with it?