@psychogyiokostas Based on your responses and other answers here, I would guess that both methods for ingesting the data (CLI and UI) is indexing all of the data, but during the indexing process, the data is ingested with the event break configuration for the sourcetype being different due to the process performing the ingestion using a different context. The props.conf file(s) controls the event breaks, but there are (can be) several props.conf files in a Splunk environment. See https://docs.splunk.com/Documentation/Splunk/8.0.0/Admin/Wheretofindtheconfigurationfiles which explains the configuration (conf) file precedence. Also, the existence of multiple contexts (i.e global and app contexts) which follow different configuration (conf) file precedence does not make it easier.
At the CLI, you can execute the following splunk command to view the props.conf settings being used for the context at command prompt, but you will need to know which stanza applies for ingesting your data. Unfortunately, the btool command is not supported in the UI, but Splunkbase contains some "btool" apps that may be helpful. A Splunk feature request could be to ask for better tools to view configuration (conf) file precedence based on an user chosen context.
./splunk btool props list --debug
P.S. The Splunk Answers tag "CLI Auto for Splunk" is for an app that I developed and shared on Splunkbase. While I appreciate the visibility for the app, your question does not seem related to this app. The "CLI Auto for Splunk" app is an automation tool for executing CLI commands on any network device with a CLI (ssh) interface. You might try searching for other Splunk Answers tags that might be more related to your question.
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