I don't see this take place on my windows machine. It may be Mac only or an issue specific to your file. If you create a brand new file with a number of records in it, can you get the same results in that file?
I didn't get the same results with a brand new single file but the problem was displaying in a very new data separated file. I'll try replicating it more closely.
It was only when I was writing the bug report that I became curious to see what commands would work. Omit didn't. Would Delete? Delete did work and suddenly the bug had disappeared.
It sounds like something funky may have happened to the file's indexing system. You can use Advanced Recover options to rebuild the file's index to see if that makes a difference. (Select only "copy file blocks as is" and "Rebuild Field Indexes Now".)
To replicate the data separation I created a new file, linked all the external files to it then tried again. It doesn't display the issue.
I first noticed the behaviour in the file a few weeks ago but didn't have time to look at it so I pulled a backup from Time Machine. The backup doesn't display the issue. It's gone from being reproducible every time to non-existent.
I'm not going to follow it any further.