MP4 AAC render audio delayed

Hi. I'm having this issue randomly when rendering mp4 files
Sometimes the mp4 is rendered with the audio track delayed by a few seconds.
Had this problem on 17 Beta, 17.0 and now today in 17.1
If I render the same timeline again, without any changes in the delivery window, the file comes out good.
I'm using h264 mp4 file with nvidia renderer, aac 192kbps audio

Are your sources constant frame rate?

I saw the same issue in the Betas with my H.265 exports (which require the nVidia card, no software option).

But I haven't seen it yet in 17.1.