Wrong sine plot when styling it

I was playing with the tutorial of Matlab. I've written this code:

x = linspace(0, 2*pi);
y = sin(x);
plot(x, y)

And I obtain the right plot:

But then I use the following command:

plot(x, y, "r--")

And I obtain this weird plot:

What I'm doing wrong?

[Steven Lord]

Let's check which plot function you're calling in each case.

x = linspace(0, 2*pi);
y = sin(x);
which plot(x, y)

built-in (/MATLAB/toolbox/matlab/graph2d/plot)

which plot(x, y, "r--")

built-in (/MATLAB/toolbox/matlab/graph2d/plot)

In particular, I'm wondering if something added an overload of plot for the string data type to the MATLAB path.

And just for completeness, what does the next line of code show and what is the output of the which call that follows it?

plot(x, y, 'r--')

which plot(x, y, 'r--')

built-in (/MATLAB/toolbox/matlab/graph2d/plot)

[Daniele Lupo]

I close and reopened matlab and the problem does not appear anymore. I don't see anything wrong with the command history, and the which command gives me always built-in (C:\Program Files\MATLAB\R2022b\toolbox\matlab\graph2d\plot)...