Mk 2 generation changed to Mk 3, with a different body shape , in 2015. But Honda Uk and various dealerships would have had some 'old stock' mk2's still available in 2015 several months after mk 3's first become available. Some buyers would have chosen a mk 2 at a discounted price, others would have paid full price to get the latest mk 3. There is nothing suspicious about it.
At current valuations a 2015 mk 3 may be worth more than a 2015 mk 2 in similar condition. But a good 2015 mk 2 at a lower price may suit you just as well and be a better buy than some 2015 mk 3's.