ZTP script losing connectivity

Hi,

I’m troubleshooting an issue with a Juniper EX4100 ZTP script and I’m trying to understand what exactly happens during provisioning.

What my ZTP script does (step-by-step):

Detects device model using cli -c "show version"

Downloads configuration from an HTTP server

Loads configuration with load override and performs commit

After the commit it runs:

request virtual-chassis mode network-port

Then the script waits a few seconds before continuing

After that it tries to run:

OS ping

Junos CLI ping

Finally it sends a single syslog message to my server

Problem description

During the initial ZTP execution:

everything works normally before the configuration is applied

after commit + virtual chassis mode step:

ALL ping tests stop working (both OS ping and Junos CLI ping)

even after waiting several seconds, connectivity does not come back

the script cannot reach my server anymore

the syslog message is never delivered

However:

If I manually run the exact same script a second time later from CLI (after provisioning finishes):

ping works normally

syslog is delivered successfully

everything behaves as expected

So the issue only happens during the first ZTP run.