No, I don't think it's unusual at all. It often takes some time before there is recovery from bud loss in palms. I have lost buds on Washingtonias, Bismarkias, Phoenix and others only to have them eventually recover. The first season, they will be somewhat stunted in growth, but growth will then take off in the following season. (I had bud loss on a Pygmy Date three Winters ago, it sulked the first season with some minor regrowth, then took off and bloomed the next two seasons!) I have one windmill that looks as bad as the one in your pic--never looked this bad but last winter was HELL. Still not growing but April and the first half of May were unusually chilly and WET.--It still has two green leaves on it and I am hopeful but planted others around it in case it does not or to create a grove if it does. I also had bud loss on a Queen palm and might have chucked it into the compost pile several years ago, but experience has taught me to be patient with palms. It still has one perfectly green leaf so I fully expect recovery this summer. Good luck!

Being that close to the house I am suprised at the damage that it sustained. I had first year trachys with no protection against the house that only had limp fronds. All I ever did was go out after a snow and sweep the palms clean with a broom.

Again, it was a BAD Winter, not only with sustained cold but also very WET!

I agree, I'm sure Tennessee caught hell that I didn't cause the Blueridge mountains blocked the jet stream.

My Trachys seemed to take for ever to recover this
spring but have come back quickly once recovery began.

One of the Fortunei is just now pushing a spear up.

The current warm temps are really/finally helping things
get caught up.

The late recovery is very normal. Usually June is the time when trachys start growing new spears if they lost them. My trachycarpus all did very well this past winter, so their new spears have been growing since April, but if they suffered from more damage, then they would also be growing a bit later.
They still have a ton of time to recover (probably right up to November!) so expect lots of new fronds very soon!
Good luck!
-Alex

It does depend on where you live and the weather you get in spring.

Last year was warm early and recovery began in the beginning
of April,this year was cool and it took until May.

This pic is of a windmill planted about three feet away from the other one. This one started recovering about a month ago. Guess all plants just move at their own pace. That's one thing about plants I am slowly learning......... not to give up before they do!

Did your windmills experience spear pull? You may want provide protection this winter.

Yes these two did have spear pull this year.

I had 2 that had spear pull this year too, one didn't come back even after peroxide treatment and all. I'll be keeping the snow off mine for a few years.