60°C is not that bad...
A bit warm for a device that must work 24/7, but it seems the temperature is not the cause for the crash
That is CPU temp, it sounds like the 5ghz radio isn’t touching the heat sink properly. Flint 2 heatsink is one big piece that lays across the top of the board with thermal pads on each chip that should make transfer. Maybe the pad is gone, off center, not touching etc, the hard crash with no logs, along with a bit higher temp that I feel is “normal” is why I say termal/hardware. my F2 runs around 50-60c in a cabinet with 35 devices and 2 WG tunnels 2 WAN, HW off with SQM. Active fan 37-49.