Chris,
A sealed box does not have the same time-domain performance as a ported box.
The port output of a bass reflex (BR) box is in phase with the sound waves emanating from the front of the driver's cone, but lags behind the front radiation by one cycle at the box tuning frequency (Fb), hence BR designs are also known as "phase inversion" designs.
This is clearly evident in Josh Ricci's test of the SVS PB13, which can be operated sealed, or with a 15Hz or 20Hz Fb.
https://www.audioholics.com/subwoofer-reviews/svs-pb13/pb13-measurements
In the group delay chart, the blue line represents one cycle at the given frequency, 100ms at 10 Hz, 50ms at 20Hz, 10ms at 100Hz, the red 1.5 cycles of delay.
The green trace of the sealed is basically 1/2 wavelength all the way down to 10Hz.
Around the 15Hz (purple) or 20Hz (black) Fb, the ported delay goes just over the red 1.5 cycles curve, above 30Hz it matches the sealed response.
As you mentioned, whether those issues are audible or not is another discussion, but the issues are inherent in the phase-inversion that makes a BR cabinet perform as it does. Can't get something for nothing...