They tested the surface of the floor, not the underside where all the water had been soaking in. Their bad. It was probably 10% higher underneath. Probably best to sand now, wait until the end of summer before putting the finish on to let the moisture level stabilize. The varnish is still going to stop even drying from taking place. You can only sand a floor so many times.
Casey

Buckling is caused by an increase in moisture content, wood swelling, and not enough room for the resulting expansion.

It sounds like it was never dried out adequately, moisture continued to move into the wood, and the resulting swelling used up all the expansion space the floor was laid with.

Tincture of time is the beast cure for hardwood floors that have been soaked.

Sometimes almost a year to make sure the wood has returned to an equilibrium with the inside of the house.

There is no good way to rush the job.

Can't tell w/o a pic if it's actually buckled or just severely cupped.
I want to take back my suggestion to sand now, because I realized you'd still have to sand again when/if the floor un-cupped. But with the finish still in place it could be a year before it is well and truly dry and stable. If you are in a hurry, just pull the floor and redo it with new material. With fans and a/c the subfloor will be dry enough within a month.
Casey

Tried to take a picture but you can't see what's going on. Perhaps cupped is a better word.

It has been one year since it was previously sanded and refinished. Based on your posts, I'm going to assume I should go ahead and try again. If I am missing something, please let me know.

Appreciate it.

"If I am missing something, please let me know. "

Have the moisture content of the wood tested.

Everyone seems to want a quick fix for hardwood floors that get wet, and it simply does not work.

If you sand cupped wood that is damp, the cupping is reversed when the boards finally dry out.
And then you need to finish them again, removing more of the wood.

A good wood moisture meter should be able to tell you if the area in question has the same moisture content as other parts of the floor that did not get wet.

I would cut out a section of subfloor from underneath the epicenter of the flooded region so the moisture level of the wet side (bottom) of the floor can be ascertained. The hole could be made with a holesaw, just large enough for the moisture meter. Each hole is really only good for one immediate test, as the proximity to moving air is going to permit that spot to dry more rapidly.
Casey

"I would cut out a section of subfloor from underneath the epicenter of the flooded region so the moisture level of the wet side (bottom) of the floor can be ascertained. "

The correct meter will penetrate far enough to allow comparison with an undamaged (dry) area.