Not marking Penta kill as a penta kill

It didn't even mark as a triple kill and in game it said "PENTA KILL" I was well within the time and everything, viewing replay shows double then a triple and on op.gg/Riot match history viewer it says max was a triple kill. I don't know if this is intentional or if your system is bugging out, but i feel like I've been robbed [zombie-nunu-bummed]

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2246896577/1?tab=overview <--Marked as triple instead of Penta