Actually this is a normal pattern in the earlier stages of T2, you may find a similar pattern with other starchy foods.
In a non diabetic insulin is released from the pancreas in 2 phases. The first phase consists of a brief spike lasting ∼10 min followed by the second phase, which reaches a plateau at 2–3 hours.
It is thought that one of the earlier changes in the development of T2 is the diminishing and then eventual loss of that first phase of insulin release. In consequence glucose levels rise rapidly after a meal but then the still existing second phase insulin 'kicks' in reducing the glucose level though at 6mmol it is still not as low as non diabetic levels would be.
It is worth experimenting with other foods, (and amounts) even other breads. Breads that are truly low GI for you would cause a gentler rise in glucose, better matched to the pattern of insulin release. This will keep glucose levels lower overall and also reduce the amount of insulin your body needs to produce in that second phase. (that extra insulin is not a good thing in the long term, causing the 'progression' of T2)
I have T1 and take insulin but (as I've written on the other thread) I've found that I have problems dosing for any of the breads I've found in UK supermarkets, including Burgen... and even though I take a rapid insulin it doesn't work quickly enough. Almost all of these breads are made by a highly industrial process resulting in light fluffly bread that is quickly absorbed by the body. I find Burgen better than most but...
At home, I normally eat denser multigrain or nut breads made locally.. If I were permanently in the UK, I think I would be looking forsimilar breads made by bakers in the traditional way .. Unfortunately that's bound to add to the cost( and unless you have a large family involves freezing it in portions since these breads contain no preservatives.)