Steps to reproduce:

1. Create a host, item and trigger with manual close enabled
2. Send a value to the item to get a problem event
3. Go to the Problems list
4. On the problem, click Update, select Close problem and click Update

Result:
"Event updated" message is shown, but the problem is still shown unaltered in the Problems list.

A refresh (manual or automatic) of the Problems list is required for the closed problem to disappear.

Expected:
In Zabbix 7.0.x this behaves differently: the Severity color is changed to white immediately after updating (closing) the problem, indicating that the problem is going away.