Social media communication is integral to framing an effective crisis response but is generally impacted by high volumes and an overload of information and misinformation, i.e., infodemic conditions. The social media connection content (i.e., information) and connection type (i.e., communications strategies) that are shared between actors (e.g., emergency response organisations and the public) underpins the development of trusted shared situational awareness for effective crisis management. This study investigates how local public health organisations use Facebook to mitigate COVID-19 misinformation and create effective trusted shared situational awareness. We show how the nature of the event and social media temporal characteristics can create information objective-subjective tensions and create misinformation on public health social media channels. This undermines an agreed and accurate representation of reality that is expected of trusted, shared situational awareness. We conclude that developing communications strategies to manage information objective-subjective tensions becomes especially important during an evolving crisis scenario where situational awareness and knowledge are developed over time and information and advice may change in response to a changing crisis conditions.