Zabbix Sender file input does not work with Proxy on 7.0+ when using timestamps.

It works as expected on 6.0, or when sending the file input directly to the server, or when there are no timestamps in the file.

Scenario:

1. [In Frontend] Set up an active Proxy:
   1. Name: Zabbix Proxy
   2. Mode: Active
   3. Proxy address: 127.0.0.1
2. [In Frontend] Set up a host with one "Zabbix trapper" type item:
   1. Host name: test
   2. Interface - none
   3. Monitored by: Zabbix proxy
   4. Item name: trap
   5. Item type: Zabbix trapper
   6. Item key: trap
   7. Item type of information: Text (but also reproduced with Numeric)
3. Configure zabbix_proxy.conf (my full config):

   ProxyMode=0
   Server=127.0.0.1
   Hostname=Zabbix proxy
   ListenPort=10052
   LogFile=/tmp/zabbix_proxy.log
   DBName=7.0_proxy
   DBUser=zabbix
   DBPassword=zabbix
   ProxyBufferMode=hybrid
   ProxyMemoryBufferSize=16M
   Timeout=4
   LogSlowQueries=3000
   

4. Start Server and Proxy;
5. Using Zabbix Sender send in a data file containing timestamps;

   ./zabbix_sender -z localhost -p 10052 -i data.csv -T
   

6. See the latest data for the item.

Result:
Only the latest record is shown.

Expected:
All records are shown.

Example of data in the file (full file attached) - the timestamps are only a few hours old:

test trap 1723413600 "000000"
test trap 1723413601 "000001"
test trap 1723413602 "000002"
test trap 1723413603 "000003"
...