I brewed a stout yesterday and everything was going great. I warmed my strike water to 68C and started doughing in. around 1/3 of the way through the malt, I realized that my temperature should have been higher (76C to be exact). So i turned up the heat and within 4-5 minutes I was at the 76C and i doughed in the remaining 2/3 of grain, which brought things down to around 68C, where I mashed for 60 mins. Now my question is.. Will the beer be ruined/undrinkable/too thin (because of the time spent at what i will assume is sub-68C since the grain lowers the temperature of the strike water), or is this a RDWHAHB scenario? I tasted the wort and it was great. The recipe is 19L, 5.5 kg of grain.

Thank you for sharing your advice/experience in advance.