  In canonical single-field inflation, the production of primordial black holes
(PBH) requires a transient violation of the slow-roll condition. The transient
ultra slow-roll inflation is an example of such scenarios, and more generally,
one can consider the transient constant-roll inflation. We investigate the
squeezed bispectrum in the transient constant-roll inflation and find that
Maldacena's consistency relation holds for a sufficiently long-wavelength mode,
whereas it is violated for modes around the peak scale for the non-attractor
case. We also demonstrate how the one-loop corrections are modified compared to
the case of the transient ultra slow-roll inflation, focusing on representative
one-loop terms originating from a time derivative of the second slow-roll
parameter in the cubic action. We find that the perturbativity requirement on
those terms does not rule out the production of PBH from the transient
constant-roll inflation. Therefore, it is a simple counterexample of the
recently claimed no-go theorem of PBH production from single-field inflation.
