Not as crazy as you may think :-)

A lot of early flowering shrubs and trees can throw a few flowers in fall. Rhododendrons are common for this as are magnolias. I even see a few blossoms in late summer-early fall on our native dogwoods now and again.

It is often triggered by cooler, wetter weather and shortening day lengths that occur in fall, especially after a warm and dry summer. These conditions fool the plant into thinking it is spring, as those are normal conditions for that time of year. Typically, this has little to no impact on the plant's ability to bloom as intended at its normal time of year.

Just enjoy your late flowers as long as they are there!!

Just for clarity's sake I am assuming we're talking about Abeliophyllum distichum, just in case anyone was hoping there is a pink version of true Forsythia. Will it grow in zone 4? It's a bit iffy in the UK and is recommended for warm spots here. Maybe it's another of those things which can take a cold winter but needs summer heat to ripen the wood. Gardengal48 what do you think? Does it do well in PNW?

Yes, Albeliophyllum distichum 'Roseum'. Supposedly hardy down to zone 5 (maybe 4b) but I have had issues with it here as well. I think you may be right in the needing summer heat thing :-)) Which we tend not to have much of..........

Upon a visit to my favorite nursery, yesterday, I noticed a good many plants, not supposed to bloom until Spring, with a few flowers. The most surprising was a Redbud tree, Cercis canadensis, I think. A few Witchhazels, of sorts usually in bloom in late Winter, had flowers, and 'Diane' had yellow ones, rather than the usual red ones.

One shown here looks like a straight (typical) mostly white one. Fall bloom sometimes comes from early-blooming shrubs like these because the flower buds have had such a long time to mature since the main bloom early in the year.