I am pretty sure that modern tires don't use release compounds any longer. At least not in the last 12 years or so. We don't even take the stickers off our race tires. Just heat 'em up in the warmers and take your sighting lap. You can hit T1 as hard as you want.
You would know better than me since you were there, but my guess is it was more slippery surface than slippery tire. What kind of tire was it? You can probably go right to the distributor to learn if their new tires are slippery and need to be scrubbed in.