Duplicate ISSNs on creation of a new titles

[iyawnis]

https://knowint.zendesk.com/agent/tickets/1544

Just for info... I looked in the access logs and saw this for the title with 2 identifiers

82.26.226.243 - dapatel@jisc.ac.uk [06/Jul/2015:14:49:47 +0000] "POST /kbplus/ajax/addToCollection HTTP/1.1" 302 -

82.26.226.243 - dapatel@jisc.ac.uk [06/Jul/2015:14:49:47 +0000] "POST /kbplus/ajax/addToCollection HTTP/1.1" 302 -

The client absolutely did send two form post entries at exactly the same time - this explains the duplicates. It's not clear to me WHY the browser would do this - but I'd be very interested to try and replicate it in the multiple and not-multiple tab scenarios [In case the button is triggering the client side script on multiple pages].

So - progress - it's definitely something to do with the client side and not the server side - still an issue we need to bottom out, but very helpful, thankyou..

1. What happened?

I manually added a journal title (in live) at around 15.55 today, I was using google chrome 
https://www.kbplus.ac.uk/kbplus/titleDetails/edit/31643

Once I added the title I copied the ISSN from the issn portal, typed ISSN: pasted in the issn and then clicked 'add identifier'

the screen now has 2 identifiers listed (see screenshot)

2. What should have happened?

I was expecting only one identifier to be added

4. KB+ Urls (which contain the KB+ IDs) 
https://www.kbplus.ac.uk/kbplus/titleDetails/edit/31643

5. Explanation of the steps we did replicating the problem 
I repeated my actions in demo but was not able to replicate the problem