earphone movement causing activation of Siri etc

I have an iPhone 7 plus and wired apple earphones ios 11.3 (beta programme). When I plug in my earphones and am still there is no issue. But if the connector (the lightening connector) wire is touched, moved or jiggled (like by having it in my pocket and walking or moving) then it causes a reaction. Either Siri will engage, or the music will be paused, song skipped, etc.

It only happens when the wire and lightening jack are touched or moved... it's driving me crazy. If I unplug the headphones and reattach it does not solve the problem. neither does a restart.