core/Common.php(297): Notice - unserialize(): Error at offset 0 of 1469 bytes - Matomo 3.13.2

Hello Matomo team,
Could you please help me, I’ve faced an issue after update from 2.16.x to 3.13.2, when run cron archive process, I get this error Notice - unserialize(): Error at offset 0 of xxx bytes in core/Common.php(297).

I saw this issue appeared in 3.9.0.

I noticed that all archive processes try to archive last 52 days
Process: climulti:request -q --matomo-domain=MY_DOMAIN --superuser module=API&method=API.get&idSite=2776&period=day&date=last52&format=php&trigger=archivephp&pid=xxxxx

Could you please explain why it should run last 52 days? Is it because of update from 2.16 to 3.13?
We had a cron setup before, it looks like this:
“5 * * * * www-data /usr/bin/php /path/to/matomo/console core:archive --url= > /home/example/matomo-archive.log” Taken from this page How to Set up Auto-Archiving of Your Reports User Guide - Analytics Platform - Matomo

And one more, it might be helpful, our piwik_log_visit table is more than 21 million records, and we use PHP 7.0. If archive process will run 52 days period each time, it will take lots of resources. Should I modify cron to keep archiving going?

Thank you.