Concordance file has duplicate items in index

Hi,

I created a Concordance file and entered text in the “1st key” column. The generated index looked great.

I then decided I no longer needed the text in the “1st key” column, so I deleted all of the text from that column using Notepad++. After doing “update index” I now have an index that is duplicated. The text from the 1st key is still appearing as a heading with all the index words below it. This duplicate area is stuck between the lines of the “good” index. I can manually delete the duplicates by unchecking “Protected against manual changes” as a work-around.

I also tried completely deleting the index from the document and created a brand new concordance file with a different name than before. I opened the new file using the drop-down under File in the “Table of Contents, Index or Bibliography” window. However, I’m still seeing the same text that I had entered in “1st key” - that text no longer appears in the new concordance file!

Trying to find out if that is a bug by going to the bug website. Possibly this is the same thing I’m seeing:
https://bugs.documentfoundation.org/show_bug.cgi?id=44152

Using LibreOffice Version: 6.1.1.2 (x64)
Build ID: 5d19a1bfa650b796764388cd8b33a5af1f5baa1b
Windows 10