dir_monitor stops reporting changes for files in directory when a single file from that directory is also watched

[sunny-gh]

When using dir_monitor, adding both a directory and an individual file from that directory leads to unexpected behavior: changes to other files in the same directory are no longer reported.

1. Add a directory and a file from that directory to the watch list:

/tmp/testdir
/tmp/testdir/file1.txt

2. Modify files inside the directory:

echo "test" >> /tmp/testdir/file1.txt # tracked
echo "test" >> /tmp/testdir/file2.txt # NOT tracked

This behavior was observed on Linux systems.
Is this intended behavior of dir_monitor, or a bug?
Thank you!