Nuendo 6 stops recording

I am a long time Nuendo user and I have an issue with recording.
My system is Dell i7, Lynx AES16 audio card, Nuendo 6
And the issue is: I record a track (one or many), after a few minutes, the recording will suddenly stop, I can still monitor the input correctly, and the only way I know it stopped it is because a waveform isn’t created anymore, it is totally flat, even if cursor continues moving and the progress bar behind the waveform is still created like if it was still recording. When it happens, I press the space bar, and then all the portion of the progress bar with a flat waveform disappears and is trimmed to the last actual recorded sample. It happens all the time, randomly, on any recording longer than, let’s say, 5 minutes. I must add that when I press the space bar to actually stop the (fake) recording, it takes a few second until I can take control again of Nuendo, maybe around 5 seconds

Any clue what’s causing it?
I see now that many people have the issue