Is this a bug in Mathematica 11 ?

[Chenkb]

I calculated a simple complex function integration using Mathematica 11.
As the screenshot shows, the only difference between the two inputs is that I set a = 1 in the second one.
However, the two outputs differ by a factor of 2.
What's wrong? Is this a bug?

 

[DrClaude]

Which version do you have? In 11.2, I get the following:

You can try and open a new notebook, set its default context to "unique to this notebook," and try and do only this integral.

 

[Chenkb]

Which version do you have? In 11.2, I get the following:
View attachment 217062
You can try and open a new notebook, set its default context to "unique to this notebook," and try and do only this integral.

Thanks. I opened a new notebook and did the settings you mentioned, but got the same wrong result.
However, to my surprise, I just changed the variable name from ε to b, and the output changed.
The version of mine is 11.1
Maybe it's a bug? and fixed in 11.2