[Oleg Pirogov]

CSV is auto-parsed from something like this:
words, numbers
wind, 10
temperature, 12

to this:

And “value of wind” is obtained through the following expression for sourceText:
thisComp.layer("testCsv.csv")("Data")("Outline")(" numbers")(" numbers 0")

Not quite understand what went wrong in your case,= as well as why are there semi-=colons in your comma-separated file.

[Oleg Pirogov]

It’s Motion Blur issue. Namely, Motion Blur applied to shape layers of nested comp with animated Scale.

Due to the big time skip at the problem point, Motion Blur acts weirdly, sampling frames far from actual frame.
The “disappearing” elements are elements with applied Motion Blur that samples frames from time where Scale=0%.

By default Scale animations are rendered before Time Remap. Collapse Transformations makes them being rendered after Time Remap.

Another fix is to set Shutter Phase = 0 in nested comp settings (Advanced tab).

[Oleg Pirogov]

Can be fixed by toggling Collapse Transformations.

[Oleg Pirogov]

I suppose, this Math.floor(clockStartTime – rateOfSpeedMilli*time) is negative most of the time.
I suppose, this Math.floor(rateOfSpeedMilli*(clockStartTime – time)) is what you meant it to be.

[Oleg Pirogov]

I’ll try and guess: have you turned on Continuous Rasterization?

[Oleg Pirogov]

How about setting var start = Date.now() before loop and adding && (Date.now()-start < 2000) to while?

[Oleg Pirogov]

So, what’s the problem with the code?
If you animate one ping pong of yours with keyframes, the code seems to do exactly what you need.

[Oleg Pirogov]

Quick question based on the screen shot: are all four properties (not just Rotation) in Transform selected when you do your ctrl+c/ctrl+v?

[Oleg Pirogov]

Possibly, you may wanna try Merge Paths.

Get a shape:

Duplicate and add background to the second shape layer:

And Merge Paths to Contents:

Set mode to Subtract and probably get something close to what you’ve wished for:

[Oleg Pirogov]

It most likely speaks of Layer Object which indeed has just those three indexed properties.
Layer Object’s subclasses (like AVlayers or Text Layers) have many other indexed properties which are counted by numProperties.