The probe heating up during scanning is normal.
The probe heating up during use is normal and expected. As the probe is handheld and does not have a processing unit connected by cable, all the probe's complex processing must be performed onboard the probe itself–resulting in the probe heating up.
As the probe naturally heats up due to the processing of scan data and there are several safety mechanisms to ensure that the probe is never risk of harm, including a warning message as the maximum heat gets close, and eventually shutting down the probe as it approaches a maximum heat (approx. 113°F).
Normal scans of less than 10 minutes or so, will likely not result in reaching the shutdown limit of approx. 113°F. However, in some instances requiring the probe to scan for extended periods of time (e.g. multiple scans without a cool down period in between), you may reach the limit and the probe will shutdown to allow it to cool.
KB-0001