Cellular Backup lag after Wi-Fi goes down?

Last night at 11:13 pm I received a notification "Base Station REPORTED OFFLINE." I kind of freaked out, because I was not at the site, I was 30 minutes away. I checked my wi-fi provider website to see if there were any outages in the area. Nope, all good. I remembered that Ring has a cellular backup system when it goes down, IF you are subscribed to Ring Protect Plus. I'm not "subscribed" yet, but on the free trial. I opened the app, and I couldn't do or see anything on my 2 ring cameras. Everything seemed offline /unavailable. I couldn't find any numbers to call to ask about what was happening. I just hoped that when I went to check the next day, no one had broken in. At 11:31pm, I received another notification "Cellular Backup RING ALARM IS RUNNING ON CELLULAR BACKUP.." That's 18 minutes after the wi-fi went down. I hope it was active immediately, and simply just taking 18 minutes to send me a notification. Thieves could do a lot of damage in 18 minutes if the wi-fi went down and there was no cellular backup during that time. The AT&T coverage in my house is great, so I don't think there's any issues with cellular network availability. After I received the cellular backup notification, it was several minutes before I was able to view any footage from my cameras. From what I could tell, they were still recording during the blackout phase? Is that correct? The system went back to wi-fi right before midnight, when I received a notification "Base Station CONNECTION WAS RESTORED." So I would just like some clarification about the apparent lag time between the wi-fi connection being lost, and the cellular data system backup kicking in. How long does that take? Are the cameras still recording during that time, and uploading once they are connected to cellular or wifi again? Thanks.