I see the from the current handling / ambient temperature curve that there is significant dropoff beyond 40 deg. It may be a problem, dependant on the actual current flow as, in some circumstances, there may be runaway.
Not something I have recent experience with, but what is the degredation of current solder (if any) with regard to operation at elevated temperature. In years past large wirewound resistors were soldered using higher melting point solder, and I often found joints had become dry over extended periods.
Tracy