You didn't post your config file. But instead of posting it, do this: Start from
emacs -Q, that is, with no init file. If you do not see the problematic behavior, then do this:
Recursively bisect your init file (by commenting-out blocks of code), until you narrow the problem down to find just what is causing it. You can use
comment-region to comment out code: first 1/2, then 3/4, then 7/8 of the code, etc. Use
comment-region to uncomment.
Another thing you can try, but don't bother until you have narrowed things down (and at that point you probably will not need to try this) is to use
M-x debug-on-entry kill-new, to see what code is pushing the unexpected entries to your
kill-ring. Just look at the backtrace to see what is happening, or step through the debugger using
d, if you want. Use
q to exit the debugger. Use
M-x cancel-debug-on-entry to cancel using the debugger.