Not all messages are backed up - random sections of conversations are missing (send & receive)

I have noticed that some messages do not get backed up and cannot find a pattern. It seems to happen to one contact more than all the others. The issue seems to be on one contact for some period of time, say a few hours. This seems to only happen about twice per week, so not very frequent. Some things that do not appear to be related to the issue:

Battery - I thought it may be power save mode preventing the backup, but this does not appear to be the case as some missing messages I believe are from when the phone had 47% (but have not proved this 100%).

Send/receive - whole sections of a conversation will be missing regardless of incoming or outgoing. An entire section of the thread did not backup.

It has happened on at least 2 - 3 contacts that I have noticed.

Messages are not deleted with in the backup time period (for example if the backup frequency is set to 2 minutes, no messages were deleted in that time).

I am running the latest version of sms backup +, on a Samsung Note 4 through Verizon with the latest all updates (automatic installation of updates fr carrier)

Thank you!

I am having the same problem! I really need these text messages. And have tried a few other apps but they aren't working the same way. if you have fixed it could you please share with me what it was that you did

I am having the same problem with my Samsung S5

My Note 8 is also missing random messages in the backup. Android 7.1.1

Maybe this helps: https://github.com/jberkel/sms-backup-plus/issues/665#issuecomment-368053785