Some Devices suddenly gone, still show in app but gone from IDE and cant be controlled

I have just had 3 devices disappear from smartthings over the last few days.

In the app they showed as offline, but when i checked the IDE they are not there anymore.

i had to rejoin them and add them again and add them to rooms/ automatons etc all over again.

this disconnect between what the app shows and the IDE is a bit of a concern for me , and i assume its only going to get worse ?

its bad enough we cant rely on routines to always run when they are supposed to, but now the devices themselves are disappearing so the routines will not run for sure!

First thing to try is clear th app cache, forse close and restart

I don’t have an answer, but it has been happening to other people. See the following. (The topic title is a clickable link)

the devices are gone from the IDE… they show in the app but they are gone from IDE, from automation’s or smart apps… .i assume clearing the app cache might also remove them from the app , though that solves nothing as i want to know why they are randomly being deleted!