A trackpad on my new macbook pro(2015) does not respond rarely. But after restart the mac, it responds for all clicks. I am using EI Capitan 10.11.4. Is it known software issue or hardware issue of my macbook 15?

The warranty entitles you to complimentary phone support for the first 90 days of ownership.

If you bought the product in the U.S. directly from Apple (not from a reseller), you have 14 days from the date of delivery in which to exchange or return it for a refund. In other countries, the return policy may be different. If you bought from a reseller, its return policy applies.

Identical intermittent problem and equipment here too. I'm on my second brand new Macbook Pro Retina. Apple has not acknowledged the problem despite many reports on different threads of the Apple forum but advises to 1) note the exact time and seconds of the next freeze, 2) contact an Apple Senior Advisor to "run a capture" which will be forwarded to Apple engineers.

Make sure the clock is already set to display seconds: Date and Time Preferences➔Clock➔Digital➔Display the time in seconds➔Show AM/PM