Which fallacy is it to think because someone committed a fallacy in one argument, they'd commit a fallacy in a different argument?

Question

What's the name of the fallacy?

If I assume, someone X has done a fallacy in other argument A1 so he will do a fallacy in another argument A2. What would be the name of this fallacy I am doing?

Answer 1

Short Answer

Hasty generalization.

Long Answer

When a thinker has specific experience or experiences, and then draws a general conclusion about them without adequate warrant, this is a hasty or faulty generalization. From WP:

X is true for A.
X is true for B.
Therefore, X is true for C, D, E, etc.

With your concrete example and the implicit proposition:

X has committed fallacy F1 in Argument 1
(A person who commits a fallacy will likely or inevitably do so again.)
Therefore, X has committed fallacy F1 in Argument 2.

Obviously, if Argument 2 doesn't actually contain the fallacy, the conclusion is false. It is a dull intellect indeed that uses induction on a single instance of experience, or if you prefer a single-data point to derive a general rule! It might be more tenable on the 20th invocation of the fallacy in an argument that one can have some comfort in such a conclusion. Of course, people can change, and hence the scandal of induction.

Answer 2

Non-sequitur.

The conclusion does not follow from the premise.

I can be wrong about many things, yet be correct about something else.