What happens if the buttons get pressed in the reverse order?
Also, can you post a picture of the remote?
The Primary solution for this in the UK used to be the fortrezz mimolite, but there have been recent reports that it does not work with the new V3 app, so I am not sure where that stands. 
Fortrezz Mimo2+ no longer supported for Smartthings
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https://www.amazon.co.uk/MIMOLite-Z-wave-Multi-Input-Contact-FortrezZ/dp/B01MU1VCZL/