Joining artefacts using Split and Join Widget resulted in the 2 artefacts removed and no new joined artefact created, what causes this?

Environment IBM DOORS Next 6.0.6.1 iFix007.

Within a module, attempted to join 2 artefacts using Split and Join Widget. The followings steps were followed:
1. Selected 2 artefacts
2. Clicked 'Join Artifacts' button on the Split and Join widget

The 2 selected artefacts disappeared. No new join artefact is created.

We attempted to search using words/text within the module, no matching artefact is found.

We attempted to search using words/text using the Search Artifacts in Current Project, no matching artefact is found.

This has happened at least 3 times.

There have been successful join attempts, however (this may be a separate issue) there are also cases where artefacts are joined however in the incorrect order.  For example:

Artefact 1 contains "ABC"

Artefact 2 contain "DEF"

The 2 artefacts are in that order within the module.

When the artefacts are joined, it shows:

"DEF

 ABC"