User would like to validate if CPU configuration control and quotas have any traffic impact over active traffic.

User has an LSYS cluster SRX and wants to confirm that no traffic affectation is involved.

This configuration change would not affect traffic in a healthy environment. The documentation does warn about not leaving 0 percent for the primary LSYS, but they do not mention any other impact on traffic:

CAUTION: The primary logical system must not be bound to a security profile that is configured with a 0 percent reserved CPU quota because traffic loss could occur.

Understanding CPU Allocation and Control

https://www.juniper.net/documentation/us/en/software/junos/logical-system-security/topics/topic-map/cpu-allocation-logical-systems.html#id-understanding-cpu-allocation-and-control

cpu

https://www.juniper.net/documentation/us/en/software/junos/logical-system-security/topics/ref/statement/system-edit-cpu.html

However, if you want to be cautious and prevent any unexpected behavior, then you can do the configuration change after business hours or when there is less traffic, just in case.