Final Cut Pro export mp4 corrupted freezes , but fine on n4v export, version 11.0.1

Hi everyone

Just exported a 6 minute movies as mp4 1080 h264 on Final Cut Pro 11.0.1 , if I export to desktop sometimes plays fine sometimes not, if I transfer to usb stick it has problems, if I play on an lg tv it has same problems.

If I export a n4v it has none of the problems above its in h264 ,

If i change the filename to mp4 from n4v it has no problems, older versions of FCP I had no problem exporting to mp4 and have done 30 to 90 minute movies , now with this version 11.0.1 if fails every time I do an export mp4 h 264 , but no problems exporting to n4v.

Am I doing something wrong or is FCP version 11.0.1 corrupted in mp4.

Please help, thank you.

I am Sonoma 14.7.1

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