Make sure your hands/fingers are dry and free from finger oils or applied options.
Oily Lotions can sometimes interfere with the touch interface.
Also, and this is NOT what you are going to want to read/learn, but this is a known issue across all iPad Pro year and models ( even the brand new 2018, 3rd gen iPad Pro models ) and it is starting to affect both the 2018 and 2017 6th and 5th gen 9.7 inch screen iPads, too!!
I am beginning to think that this is growing issue that is NOT hardware related, but either iOS 11 and/or iOS 12 related bug.
I have a 1st gen, 12.9 inch screen iPad Pro still running iOS 10.3.3 and I am NOT experiencing these recent intermittent touch screen issues.
The best you can is alert Apple to this growing issue.
The only way to get Apple to, DIRECTLY, listen to you is to use their feedback portion of their website.
iPad Feedback
http://www.apple.com/feedback/ipad.html
Cognizant Apple employees read ALL feedback generated from all of the various feedback pages and transfers the data to the proper and responsible Apple teams and personnel , but NO Apple employees will ever respond with any type of direct, individual replies from the feedback you post.
The more users that post product feedback about any product issue, the faster Apple is made aware and starts working on a fix/solution for a future software update.
Also, you may want to phone contact Apple, directly in Cupertino, California, and calmly talk to an Apple customer service employee about this issue via the link below.
Contact - How to Contact Us - Apple
Good Luck to You!