Given constraints of speaker and room with reflections, the phase wraps will always be present when viewing IR with long windows. With center to center driver spacing of about 90mm, and off axis response at 30 degrees to 10kHz the frequency response ripple above 3kHz is unavoidable. Smoothing used hides it. Shorter windows for FR remove many room reflections.
With line array 2.3m tall, measurements made at 3m, and about 1m from floor place top driver about 80cm further from microphone than closest driver. This has delay somewhat more than 2ms; implying use of correspondingly short window to only capture direct response of speaker. Quarter wave effects start at about 500Hz, speaker starts showing that it is not a single source.
Your waterfall plot:
uses 3.1ms window and shows FR ripple. Ripple in FR equates to ripple in phase response.
Even single 3.5" full range driver shows itself not to be single source at higher frequency. When I correct a response of such driver to flat within 0.2dB at measurement position, and then move microphone a few millimeters, ripple becomes evident.
Even single tall and narrow ribbon as line array will show ripple.
All speakers are compromise, some are easy to live with, like yours.
With line array 2.3m tall, measurements made at 3m, and about 1m from floor place top driver about 80cm further from microphone than closest driver. This has delay somewhat more than 2ms; implying use of correspondingly short window to only capture direct response of speaker. Quarter wave effects start at about 500Hz, speaker starts showing that it is not a single source.
Your waterfall plot:

uses 3.1ms window and shows FR ripple. Ripple in FR equates to ripple in phase response.
Even single 3.5" full range driver shows itself not to be single source at higher frequency. When I correct a response of such driver to flat within 0.2dB at measurement position, and then move microphone a few millimeters, ripple becomes evident.
Even single tall and narrow ribbon as line array will show ripple.
All speakers are compromise, some are easy to live with, like yours.