You may cross check the value of these counters using 'dfm perf data retrieve' CLI for the particular counter.
Check the value of the counter to see if it has exceeded the threshold.
Also paste the output of the 'dfm perf threshold list -x' CLI as well.
Please note that the event would be marked history if it has breached and back to normal. For e.g: Letz say the threshold value was created at time t0, the threshold value is 50% and threshold interval is ti secs. At time t1, if the value of the counter is 51 % (consistently above 50% for the threshold interval i.e., t1- ti time duration), then perf event would be generated. However, at time t2 this event would be marked history (and hence NMC won't show in the console) if the value of the counter falls below 50%. Please verify if this condition applies to your case.