Terminal cannot print all output. Part 2

[Friday32]

I'm running into a similar problem to issue #36787 that is now closed.

I have a console app written in C using Visual Studio Professional that is being called in a vscode task.

The output in the Terminal window should look something like:

[ 7%] First line of text.
[ 14%] Second line of text.
[ 21%] Third line of text.
[ 28%] Fourth line of text.
[ 35%] Fifth line of text.
[ 42%] Sixth line of text.
....

But, I might see something like:

[ 7%] First line [ 14%] Second line of text.
[ 21%] Third line of text.
[ 28%] Fourth line of[ 35%] Fifth line of [ 42%] Sixth line of text.

It looks correct when the data is passed to the Output window instead of the Terminal window.

In my application, I have the lines that turn off buffering:
setvbuf(stdout, NULL, _IONBF, 0);
setvbuf(stderr, NULL, _IONBF, 0);

The output looks correct if when commenting out these lines, but I suspect you can still get the error as all my printfs() have a strings that end with a newline character.

[Tyriar]

This is likely related to winpty, tracking in #45693