Video with an possibly audio quirk

The subject was filmed at our non profit site using two cameras and as a audio backup a digital voice recorder was used.
In the film with Camera B the audio is as expected with the usual sync.
In the film of camera a the audio feels as though synced however there a unusual gaps as the speaker is talking. If I unlinkded the audio from camera a's timline and insert the digital audio track that gapping anomoly remains.
I have three short films. Camera B with its linked audio; Camera A with its links audio; and Camera A using a digital audio track from the digital recorder.
If possibly let me know why there is a difference from the audio playing on Camera A and the Camera B. Thanks!

Archive Test Site Audio Track Discrepancy Camera B
https://youtu.be/CfGDd9FteoM

Archive Test Site Audio Track Discrepancy Camera a
https://youtu.be/pUrLcWdzpFw
Archive Test Site Audio Track Discrepancy Camera a digital
https://youtu.be/FD7RCY5zhxE