For some reason when my iPhone uses the extender even with private WiFi address off in the tether app it says it's not transmitting any upload or download data And in the total traffic.
This isn't a problem for any other device. Strangely if said iPhone is on the main WiFi it's completely fine. And it's total traffic remains unaffected but won't update again if it turns to the extender.  This isn't a problem for all my other devices. e.g Dell laptop. 
The extender is in one mesh mode. 

 

main router Archer AX55pro

extender re505x

device affected: iPhone 12 iOS 26.1 with private WiFi address off