So does this mean we need to stop trading BTC on GDAX until Coinbase considers the issue resolved after the fork?

What if we haven't touched the BTC on GDAX in a while? Wouldn't those chains still exist post-fork?

They left a bit of ambiguity in there specifying that we should move BTC out if we want access to both Unlimited and Core. But I'm unclear what to do since it doesn't matter to me either way. I just don't want to lose anything and I want the ability to continue trading.