Custom ini settings:

[Debug]
always_archive_data_day = 1

[General]
time_before_today_archive_considered_outdated = 1

First I tracked a new page view

matomo.php?rec=1&idsite=1&action_name=foo&send_image=1

Timezone of the site is America/Los_Angeles

The log_visit.visit_last_action_time for this visit is 2020-07-20 01:41:44.

I then view the reports like this

index.php?module=CoreHome&action=index&idSite=1&period=day&date=yesterday#?idSite=1&period=day&date=2020-07-19&segment=&category=General_Actions&subcategory=General_Pages

The date is 2020-07-19. However, nothing is being archived since Loader::canSkipThisArchive returns false because hasSiteVisitsBetweenTimeframe() returns false:

The to and from date is correct. However, in the UI I can't select the 20th July as this day as not started yet. My local time is 1:40PM July 20th NZST.

When using Matomo 3 everything seems to work as expected. Once I disable the canSkipThisArchive check, it starts the archiving. And interestingly it uses a different time:

and it is showing data for this report

It seems bit random that Matomo would use two different times? Somewhere the time is off?

The time that canSkipThisArchive used seems correct to me?

The LogAggregator class uses this method:

and canSkipThisArchive uses a different way as it uses this logic

Something seems off. Then realised skipThisArchive was creating the wrong time as it was generated the time for UTC 0am to 23:59 in the different timezone. When it should have created the UTC time for US/LA 0am to 23:59:

To make it short, skipThisArchive should use same logic as logaggregator see PR #16221