Caution amending backup - files and folders missing from backup

I set-up a backup job to backup the 'videos' folder in my home directory to an external disk - it worked fine.

I amended the backup job to also include my 'pictures' folder in my home directory.

The second (incremental) backup was very fast, so I suspected something was wrong.

I checked the backup using the 'explore' option and I see that the 'pictures' folder was not backed up.

I discovered that it is better to include the whole 'home' directory, and use the 'exclude'.

I have raised a ticket with Support.