Yes, some of mine always flower some in fall. Especially the low chill types. But it's usually only 5% or less of total fruit buds on the plant. Usually 1% or less. Some like Star have higher chilling needs and don't flower early very much.

I try to force some in fall because in my greenhouse it never drops below freezing. This gives me a few fruit in winter or early spring. Last winter I had some great fruit especially from Santa Fe. That variety is usually very sweet and low acid. Because of the cool temperatures in winter the fruit was sweet/tart and unlike anything you'd get in hot weather.

Late summer pruning will force some bloom. I probably pruned too late this yr but do have some flowers opening now. Many look just like yours which is kind of half flower and half vegetative. The shoot ends in fruit flowers/buds not vegetative buds like a normal summer shoot. Those fruits if you could save them would be up to double normal size. I'm trying to force those type shoots with the big berries at the end of the shoot fall or spring.

Our northern highbush blueberry shrubs always produce a few flowers in September or October. All it takes is a run of cool weather followed by a run of sunny and warm weather. Since we will have bees around in the fall, the flowers are pollinated, and there will be a few green fruit as the shrub enters winter dormancy.