Turbo Mode seems to affect a particular CSF project in 3.0 differently than it does in 2.0

[techwonder21]

Expected Behavior

Turbo Mode works - https://scratch.mit.edu/projects/23883903/#editor

Actual Behavior

Turbo Mode does not work - https://beta.scratch.mit.edu/#23883903

Steps to Reproduce

1. Open this project up in 3.0
2. https://beta.scratch.mit.edu/#23883903
3. Click the green flag
4. Run Turbo Mode
5. Notice that the Turbo Mode runs much slower in 3.0 than it does in 2.0
6. Also notice that the outcome of Turbo mode does not match it's 2.0 version

Operating System and Browser

macOS High Sierra, Chrome 69

[Mr-Dave2]

Are you sure that using turbo mode changes the outcome? On my computer the changed picture looks the same with or without turbo mode (Scratch 3.0, Windows 7, Firefox 62.0.2).

The problem acts like it can sense the previous black stamp. I added a 1x1 costume and when I used that for the sensing costume the result is much closer between Scratch 2 and Scratch 3.

Also, if you press space key the program will stamp out horizontal lines and it looks to me like there is a slight difference in the line widths between Scratch 2 and Scratch 3. So I think this is another rendering issue that looks like it might be something else.

[techwonder21]

Thanks @Mr-Dave2 it looks like Turbo Mode is not the issue.

The 2.0 sprite (size 3x3), when put in 3.0 can sense the previous black stamp, causing the entire screen to stamp black across the project (not intended).

Steps to Reproduce:

1. Open this project up in 3.0
2. https://beta.scratch.mit.edu/#23883903
3. Click the green flag
4. Run Turbo Mode (to be quicker)
5. The outcome of Turbo mode does not match it's 2.0 version

This is still an issue although we may be able to use this workaround for the time being.
@rschamp