I have since got a work around from the developer team. The steps are:
- Open both presentations
- Copy the slides you want transferred.
- Paste the slides into the destination presentation. They will show the destination formatting.
- While the newly pasted slides are still selected, click on the little clipboard icon when it shows and from the drop down menu, select "Keep Source Formatting". The newly pasted slides will show the source formatting.
In the meantime, they are trying to find the cause of the problem.