Ethereum flashcrashed on GDAX losing 99.99% of its value earlier today landing at 10 cents

Yes this is off topic from zcash but should be on your radar if you are vested in this area.
There is a lack of reporting on this matter everywhere you look.
Some of the press are reporting on the amazing rebound from mid 200s and a crash to 10-16 USD, but absolutely barely anyone aside from a few independents are covering this.
Its as if they want to shrug off the whole scaling issue which is now becoming abundant with all these ICOs dropping on Ethereum.

See for yourself

If this isn't a wake up call, anyone playing with ETH needs to have a serious reality check.

But it did went back to its original value after minute.

So my question is that: Will Zcash have same issue like this in future?

That's not the point.
People buying their first bitcoin commonly buy through coinbase which relies on gdax.
Not first time for gdax this year

That's dependable on whether the exchanges start to implement circuit breakers to avoid such volatility before zcash is added.
GDAX need to get their act together and stop focusing on making their UX flashy and focus on tightening up their back-end.
Otherwise the next flash crash shall be larger than the last as you can guarantee others are now scraping their order books one by onem by the second waiting for the next..