Why didn’t I drop out of ketosis after drinking beer.

Hi, I’ve been on the keto diet since Jan2 this year. I have done the diet 2 other times in the past. I usually do it to lose weight after I gain enough to have problems tying my shoes. I lose 30-45 lbs on a very strict diet and then after  about 4 months , I start eating junk again and over the next two years, I gain it all back again. Well I’m loosing weight again and am very strict while trying to drop the weight fast.  I don’t have any problems with dropping 40 lbs in 4 months. 
 

I am a 51 year old male 5’10”. I started the diet at 237lbs on Jan 2, 2023.   I mostly stay below 25 net grams of carbs per day and usually only hit half that. Occasionally I will have a chewy meal for birthdays and date nights and holidays. This time around I’m doing intermittent fasting along with calorie reduction and keto. I fast from about 6pm to 3 pm the next day. I eat all my calories in about a three hour window and sometimes eat them all in one meal.  I have been averaging eating about 1500 - 1800 calories a day. My Fitbit says I burn an average of 3000 calories a day.  I am currently at 200 lbs as of this morning. I have been dropping about 3 lbs a week. My goal is to get to 190 with the calorie deficit and then slow the roll and try to maintain a 1-2 lbs drop per week for the rest of the year or until I hit 175lbs. 
 

Well there are my specs so here is my question.  I had a cheat meal on st patty’s day. I had 3 - 16 oz  cold smoke beer that supposedly had  many carbs. I think the day measured about 88 net carbs.  Well over my 25 net daily allowance. I measured my blood ketones in the morning to find my ketones at 1.4 mmol. Later before dinner it was up to 1.9 mmol. I thought for sure the beer would have kicked me out of ketosis but it doesn’t look like it. I thought my meter was broke so I tested my wife who is not doing keto and she was 0.4 mmol. So that sounds right. So why didn’t I drop out of ketosis?