Blood sugar spike while low-carbing?

I'd really appreciate if someone could help me understand what happened, and why.

I'm newly-diagnosed, probably type 2, and have been eating to my meter. I realised I can tolerate very few carbs, so I'm on about day 3 of drastically-reduced carbs. I have a typical type 2 history (gestational diabetes, pre-diabetes on and off).

I'm testing frequently and I've been very steady all day at around 6.3. I didn't eat at tea time as I was out doing the food shop (ok, I was reading all the labels of everything in Tesco and enjoying the peace and quiet away from my kids).

After doing the shop, I had a snack - a long seafood stick for 6.8g carbs and a Fulfil bar for 11g carbs but 9.2g polyols, so really 1.8g as I understand polyols aren't absorbed.

I tested about an hour later, before dinner, and got a reading of 10.6.

It seems a very large jump for the small amount of carbs I had. I've not experienced that before and it's thrown me as I thought I was doing well.

I'm on 30mg slow release gliclazide and dapagliflozin.

Any thoughts?

Thanks all, I think it must have been a contaminated sample as I checked and double-checked the labels.

I had the same thing today and tested before and after, and got 5.8 for both.