Part of customer board on LMZ22005 is occur periodic Vout drop.
Please let me know about these reason and tend to defect failure or application issue.
Also, please let me know if there is anything else that needs to be checked.
【Condition】
・Power supply: PCIe power supply (12V)
・Vout: 5V / Iout: less than 1A total
【Problem】
・5Vout occur decrease periodic, waveform is below;
ch1：PCIe 12Vin、ch2：5Vout、ch3：0.9Vout、ch4：Vfb
※0.9V is 5V → 0.9V DC/DC that output side of LMZ22005, 0.9V is shut off by falling reset threshold after 5Vout decrease.
Zoomed: 
【Other waveforms】
・ch1：PCIe 12Vin、ch2：5Vout、ch3：0.9Vout、ch4：Ven
・ch1：PCIe 12Vin、ch2：5Vout、ch3：0.9Vout、ch4：Vss
Zoomed: 
・ch1：PCIe 12Vin、ch2：5Vout、ch3：0.9Vout、ch4：Vout_ripple
※I couldn't measure the waveform for Input Output current, because of the condition for customer's board.
If you need a detailed circuit information, would you please contact me directly by email?
Best regards,
Satoshi
