If the RF activity is caused by an unexpected Bluetooth scan during boot, that is problematic given the numerous privacy design flaws of Bluetooth. A Bluetooth scan could allow an eavesdropper to uniquely identify the device that is booting up. A WiFi scan would be less concerning, given the randomly generated MAC addresses used for scans when not connected to an access point.
Bluetooth operates in two modes: Bluetooth LE (Low Energy) and Bluetooth Classic (also known as Basic Rate/Enhanced Data Rate or BR/EDR). Both of these technologies have weaknesses that allow for passive eavesdroppers to determine hardware identifiers or bypass privacy defenses and perform long-term, unique tracking of devices. There are lots of research papers on attacks that de-anonymize Bluetooth devices:
The papers above are performing attacks against Bluetooth devices that include mobile phones (Google Pixel, Apple iPhone, Samsung, etc.). The papers above also show the attacks can be performed at longer distances.