Yes it is a ntc(about 4 ohms).Appears to be a NTC rather than a MOV, wired in series with the load to take power inrush surges.
Max.
It is possible that it could work for years without any problems. Two mosfets appear to have shorted out within two months.You will be OK if the part you replaced with are genuine.
It could be that the first mosfet failed due to age, and that I was just unlucky with a faulty replacement. To be honest, I don't think it's worth
the risk to find out.
The replacements were bought from a reputable company and have equal or better voltage and current ratings.