Yes, it definitely is.
Flying 100 hours every month, flying west, east, north, south, morning, afternoon, evening, night flights all mixed up takes its toll! This has never been done before. Also, there is obviously not enough recovery time. Even some in house doctors somehow recognise it is becoming too much.
What is also a problem is the cumulative effects of all those tiring flights and the lack of recovery time over a longer period. It would be ok to fly 100 hours/month once a year maybe, but doing it month in month out is not good.
Over the last few months, I have seen guys showing significant signs of fatigue. I am slowly becoming one of them myself.
The rosters are legal, sure, but extremely fatiguing nonetheless.
So is fatigue an issue? Yes it is...