I had that problem last week it become bad but not only on dcoy
i expierenced it also on other servers
suddenly during the game ping raised up to 300 sometimes
(normal ping is 35-50) but when
endtitles appeared it was stable very odd
I asked other dutch players if they had these problem's too some did some don't
after 2 weeks freakinout about my ping it suddenly stopped being unstable!
I still don't know what it was.
i do know cable company are doing alot of servicemaintenance to
builld a network for hotspots internet.
check your internet provider or try to reset your modem'
Good luck and I hope you'll find the problem