T490 has a heart attack when an extra stick of ram is inserted, is this normal?

My T490 arrived with a soldered 8 GB of RAM, and inserted 4 GB of RAM, about 3 years ago. I upgraded to a total of 16 GB of RAM later.

However the laptop started to get worse, sometimes instantly shutting down after pressure was applied on the laptop, requiring a push of the emergency reset button to have it working again, and later on being straight up inoperable, with even a slight pressure on the laptop keyboard freezing and breaking the system.

This lead to the motherboard being replaced via warranty repair, however that seemed to only delay the problem, resuming to become more worse.

The only solution I found was unplugging the extra stick of ram, and has been working as normal ever since, however at 8 GB of ram that I feel is slowly becoming more unbearable due to uni workloads.

Recently I am thinking of attempting to reinstall the extra gb of ram without my T490 breaking again. I would like to know if there's anything wrong with my T490, or if there's any RAM limit to the laptop I don't know about?