Timeline tweening and as3 tweening. Animations run jerkily

Problem

Animation jerky when published from Animate. CC, on a magic bar MacBook Pro 15" with 5k LG monitor attached.

This problem shows on two identical set-ups.

Description

When publishing from Animate (publish set to Flash Player or to AIR)

Two symbols tweening on the timeline run jerkily.

The frame rate drops  from 60 to 40 fps whilst the TweenMax animations run.

One greensock Tweenmax tween on a small symbol runs jerkily. But three of the same tween together are very jerky.

The frame rate fluctuates constantly between 60 and 32 fps whilst the TweenMax animations run.

Steps to reproduce:

stage size 1920 x 1080, fps 60.

A. Tweening in timeline

Create a circle symbol with gradient fill. 250 pixels x 250 pixels

Classic Tween one copy of the symbol from left stage to centre. pause it for 60 frames and play it backwards again

Add another copy on the right and move that one to the centre and back. Have the whole run timeline over 180 frames.

B. Tweening in AS3

With a small linked symbol 'Body' (gradient fill). Create a TweenMax tween on the x axis over two seconds, and set it to yoyo and repeat.

Add four of these to the stage at various y locations.

//needs greensock TweenMax

public function makeAThing(yloc:int):void{

  var c = new Body()

  c.gotoAndStop(1)

  addChild(c)

  c.x=100

  c.y=yloc

  TweenMax.to(c, 2, {x:800, repeat:-1,  yoyo:true, repeatDelay:1})

  }

Configuration and Equipment

MacOS Sierra 10.12.3

Adobe Animate 2017.1 release, build 16.1.0.86

Macbook Pro 15" 2.7Gz, 16Gb RAM, Radeon Pro 460, 4096 Mb

Monitor LG Ultrafine 27" 5k. Or Monitor LG Ultrafine 21" 4k.

Notes

Frame rate is more consistent when no external monitor used. But AS3 Tweens still jerky.