The deployment of energy storage systems, especially lithium-ion batteries, has been growing significantly during the past decades. However, among this wide utilization, there have been some failures and incidents with consequences ranging from the battery or the whole system being out of service, to the damage of the whole facility and surroundings, and even personnel injury and casualties. Some of these events have documentations on the event details and findings. This mini review paper contributes to the existing literature related to lithium-ion batteries thermal incidents by presenting and discussing the documented findings of these most recent incidents. In some cases, the lithium-ion battery system has complied to the most recent standards related to battery systems such as UL 9540 and UL 9540A thermal runaway propagation test; yet fire incident and propagation nonetheless occurred. Hence, the lessons learned from these documentations are valuable for the next development of the battery system and technology. Some key lessons from selected cases will be discussed, including specific lithium-ion battery system risks and their countermeasures, while covering several related standards, and identifying possible gaps in the existing standards.