SSL stripping active

Out of the blue today Intercept X on my iPhone has been notifying me that the home WiFi it is connected to  (Virgin) has a "SSL stripping active" issue. I see from old posts here that this is (usually?) a false alarm but how can one tell? My understanding of SSL stripping is that it is more an issue for web servers than clients and I'm unclear what I am supposed to do about it (I have switched to another provider protem). What is it that Sophos has actually detected, and between my client and where? iOS 14.6 IX mobile