HTML5 Responsive Layout - Output URL includes '%2F' in the path. Why?

Hi,

I'm using RH2015.

I have generated a responsive layout in both a single project and a merged project and in the generated output the path is being written as per.....

index.htm#t=mergedProjects%2F10act%2Fact%2Fact_rl5.htm

Why in the URL path is '%2F' being added?

This is what I would expect to be in the path:

index.htm#t=mergedProjects/10act/act/act_rl5/act_rl5.htm

If I change it to this manually the topic displays correctly but if I click to another topic then back the path reverts back to having '%2F' in the path.

Anyone know why this is happening?