Yes, it was how Meraki process the information for Location Analytics that was changed - nothing to do with the client, or the MR firmware.
“Passersby are probing wireless devices detected by a Meraki AP, whose probes and dwell time did not meet the requirements to be considered a visitor. If clients are using randomization techniques, location analytics may be detecting falsified/anonymous client IDs, and this should be considered when analyzing location data.
With some vendors implementing MAC randomization on client devices, we made a change in the way we calculate the Passerby devices in the Location Analytics tool to keep the data accurate. A unique non-randomized MAC address needs to be detected for more than 1 minute interval for the client device to be classified as Passerby. If the device using MAC randomization the MAC address used for probe requests changes multiple times within the 1 minute interval. We will be eliminating these MAC addresses from the Location Analytics computation and the Scanning APIv2 output as well.”
From: https://documentation.meraki.com/MR/Monitoring_and_Reporting/Location_Analytics. This doesn’t provide the exact date of the change but other posts in the Meraki forums have similar experiences and identify this time, https://community.meraki.com/t5/Wireless-LAN/MAC-IOS-Randomization-quot-Fix-quot-results-in-70x-drop...