Issue Plesk stuck during update, now got daily slowdowns until "plesk repair all -y"

[Jacek]

Dear, we noticed huge slowdown or our plesk - prestashop page. Nothing were reconfigured, I found that 2 days ago plesk installer get stuck on 6 updates. Needed to

- plesk installer update
- plesk repair all -y

Then I could start updates in GUI.

Unfortunetely since then we got daily slowdowns, tried restarting PHP, Nginx, Apache, changing PHP for other handler - no effect. Disabled all caches - no effect.

Only - plesk installer update make page work fast again.

How to find the issue?