Tos26 the log is good .. and appears to show connman attempting to connect to 0/1/2/3.pool.ntp.org servers. The DNS record for each host returns multiple A records and each time you query the ordering of A records in the response changes (aka DNS "round robin" load balancing). Connman picks the first entry in the list of A records and makes an NTP request to the server. If it gets no response it goes through the list of NTP servers and repeats. If it completes the entire list, it goes into a retry pattern that waits progressively longer before trying the list again. Eventually it hits "95.81.173.74" from 3.pool.ntp.org which responds and the time is adjusted. It will now continue to use that server unless it fails to get a response (and the process restarts) or you reboot the box (and the process starts again).
Connman devs modified the ntp workflow in the last year based on feedback we gave about common ntp failures on Pi hardware. I was involved in that and connman is following what I understand to be updated workflow. I can't explain why you get no response from 3-4 ntp servers before finally getting a response. Some ISP's do block NTP but they're not common and it tends to be a "block everything apart from our own server" and this looks to be more random.
Configure "95.81.173.74" as the only NTP server and reboot. Does that solve (work around) the problem?