It seems that the automated detection of hardware and the update tool simply can't be trusted... I did a total wipe of drivers and used the CD one into update (instead of using auto-detect tool) and then got correct result. I suspect there is a driver’s version mismatch between the RX570 and RX580 into auto-detect/update tool.
If it can help anyone: check that the driver installed is matching your hardware type. It might "work" but under some circumstances (not all games, not all actions, etc).
Problem : when updating from 17.x to 18.x my GPU detection goes to RX570 to RX580.
Additionally, I noticed that the CD driver installed additional programs that the auto-detect tool didn't (Visual studio packages for Win7 x64). Maybe the issue of crashed come from that that missing software.