Multisite triggers UPDATE queries on _sitemeta of almost 150k character

[yuluma]

I was checking mysql to see why the binlog was so huge. I temporarily wrote mysql queries to general.log and after that took an evening to run some checks.

I first checked what qeuries were the longest and then focused on the _sitemeta and checked again:

root@webshops04:/var/log/mysql# grep -oP "UPDATE.*wp_ec9ff84fca_sitemeta.WHERE." /var/log/mysql/general.log | awk '{print length, substr($0, 1, 150) "...", substr($0, length($0)-100)}' | sort -nr | head -n 20
145439 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602500;s:8:"response";a:23:{s:21:"cardgate/card... updater.php";s:5:"0.2.1";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'
144408 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602574;s:8:"response";a:23:{s:21:"cardgate/card... updater.php";s:5:"0.2.1";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'
143388 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602547;s:8:"response";a:23:{s:21:"cardgate/card... updater.php";s:5:"0.2.1";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'
141499 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602524;s:8:"response";a:22:{s:21:"cardgate/card... updater.php";s:5:"0.2.1";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'
139144 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602522;s:8:"response";a:23:{s:21:"cardgate/card... -add-on.php";s:5:"1.1.8";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'
137255 UPDATE wp_ec9ff84fca_sitemeta SET meta_value = 'O:8:"stdClass":5:{s:12:"last_checked";i:1726602502;s:8:"response";a:22:{s:21:"cardgate/card... -add-on.php";s:5:"1.1.8";}}' WHERE site_id = 1 AND meta_key = '_site_transient_update_plugins'

In wp_config i switched the CRON off and manually added a cron for each subsite (i run a site per domain, 3 in total)

So now i'm wondering, why would WP Multisite update this cron meta value time over time with a query of almost 150k characters? Why can't the system check only once a night for updates?

I've searched on this meta_key online but no results so I wonder if this isn't an issue or am i the only one facing this issue?