[MT-AU Public] RBMetal2SHPn wireless thermal shutdown?

Can anyone tell me if there is a thermal shutdown arrangement within the wireless component of a RBMetal2SHPn? I have a pair of RBMetal2SHPns on a 13km link and if I turn up the power to get good throughput, the RBMetal2SHPn sending the data shuts down its wireless after some minutes of maximum throughput. The wlan interface still shows as up, but snooping from the shut down end reveals no stations where it normally shows many. It requires a reboot to get it going again. It feels like a thermal issue, but the system temperature does not change, and its cold outside . Any help appreciated. Steve.