Cloudron 10.0.5, Ubuntu 26.04.1, MySQL 8.4.11 (also seen before
the OS upgrade on 22.04 / MySQL 8.0.46), ~100 apps, mail enabled,  eventlog 
table ~38k rows.

Symptom

The box service exits through the uncaughtException handler and is restarted
by systemd. 3 times in 23 minutes today ( NRestarts=3 ), and 3 times on
2026-09-24:

From uncaughtException handler.                                           
BoxError: Lock wait timeout exceeded; try restarting transaction          
    at Object.transaction (box/src/database.js:58:15)                     
    at upsertLoginEvent (box/src/eventlog.js:57)                          

While box restarts, the dashboard, LDAP/OIDC and mail authentication are
briefly unavailable.

What I found

The stack points at the  UPDATE  in  upsertLoginEvent() . Because of
 DATE(creationTime)  in the WHERE clause, MySQL doesn't use
 creationTime_index  and scans the whole table:

EXPLAIN UPDATE eventlog SET dataJson='{}' WHERE action='user.login' AND   sourceJson LIKE '%x%' AND DATE(creationTime)=CURDATE();                     
type: index | possible_keys: NULL | key: PRIMARY | rows: 32747 | Extra: Using where                                                                 

On a test MySQL I could reproduce the lock wait: with that UPDATE open in
one transaction, a write to an unrelated  eventlog  row from a second
session times out.

Some callers (the mail auth paths in  app-bridge.js  and  ldapserver.js )
call  upsertLoginEvent()  without  await , which would explain why the error
ends up in the uncaughtException handler.

Happy to provide more logs if useful.