Thanks guys!
How did this one work out for you? Any revelations as to what you think might have happened? Did you add any yeast nutrient to the boil kettle for your repitched slurry?
The fermentation is strong now - am ramping up to finish out now.
Sample tastes appear to be fine albeit it is fermenting beer so we'll see when it's all done.
I did add wyeast nutrient to the boil. All very perplexing.