Need to investigate slight overshoot of phase stats

[seongsujeong]

Checked for duplicates

Yes - I've already checked

Describe the bug

There was a slight overshoot in the stats of phase during pytest in circleCI. Especially, the minimum value of the phase was slightly smaller than -np.pi.
More information to be found at the comment in the PR below:

#162 (comment)

What did you expect?

I expected [...]

Reproducible steps

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Environment

- Version of this software [e.g. vX.Y.Z]
- Operating System: [e.g. MacOSX with Docker Desktop vX.Y]
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[vbrancat]

@seongsujeong can you please verify if we need to investigate this issue?

[seongsujeong]

Suspecting a truncation error. I’ll start taking a look.