Hi @maham1243 ,
Welcome to Google Cloud Community!
Have you tried to click the Underprovisioned resource warning on the instance health issues? It will show some insight and recommendation. Because, it might be not only the CPU utilization that affects the performance of the instance but other metrics as well such as memory components and usage specially since the instance is using only 614 MB. You can check the other available metrics on the chart.
Also, to check if there is really an underprovisioned instance, you can use the Recommender to help you detect instances that have high CPU and/or memory utilization. It then provides recommendations for how to optimize the instance.
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