Steps to reproduce:

I updated both Zabbix Proxy and Zabbix Agent to version 7.0 (obviously also Zabbix Server to version 7.0)
Zabbix Agent2 is running as "Local System" on a Windows Server 2022
in zabbix_agent2.conf I set:
AllowKey=system.run[*] 
Plugins.SystemRun.LogRemoteCommands=1

On the Zabbix Server side I created a simple script to restart a [Windows] service ( sc stop "servicename" && sc start "servicename").

I Used Template: Windows by Zabbix agent active for that agent

When used an action that recall above scritp:

a. in zabbix server GUI i see

b. In zabbix_agent2.log I see: .... [SystemRun] Executing command:'sc stop "WMI Mapper" & sc start "WMI Mapper"'

Immediately after Zabbix Agent 2 service I find it stopped and in the Windows event log I see: "The Zabbix Agent 2 service terminated unexpectedly..."