THE BUG IS NOW FIXED.
You can manually disable this addon or update to the latest version and it will do it for you.
If for some reason you wish to keep using this addon use version 10.2.6.6. https://www.curseforge.com/wow/addons/leave-spam-channels/files/5206231
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Due to a bug in 10.2.6 the General, Trade and Services chat channels are re-joined upon login and applied to all chat windows. This bug is very annoying.
This addon leaves the "Services" channel automatically every time you zone in. "Trade" and "General" are turned off for all windows except ChatFrame 1.You can alter the spam channel with a small edit to the source code. You can also send Trade to it's own window if you need that functionality.
local spamWindow = 1 -- general/spam window
local tradeWindow = 1 -- trade window
local leaveGeneral = false
local leaveTrade = false
local leaveDefense = true
local leaveServices = true
Hopefully this is fixed soon.