I suggest you remove all flashplugin packages you have installed at present that include flash, pepperflash or gnash in their names, ie,

browser-plugin-freshplayer-pepperflash
pepperflashplugin-nonfree
flashplugin-installer
gnash
gnash-common

then enable the canonical-partner repos and install just the adobe-flashplugin package which will also pull in adobe-flashplugin-gtk; that should now be the only packages needed in any browser.
Chrome uses its inbuilt pepperflash system so no need to worry about that, if you use Chrome.