Placeholders should retain their ID numbers when a new Layout is applied
Content on slides changes position when the layout is changed, then changed back again.
Demonstration: Create a slide with the Comparison layout. Enter unique text in each placeholder, so you can identify the placeholder from it's text. Change the Layout to Title. Change it back to Comparison. Some content is now in a different position that it was originally.
Apparent Cause: If save each state as a separate slide, then examine the XML, you'll notice that when the Title layout is applied, the ID numbers of the placeholders are preserved. Then when the Comparison layout is reapplied, the existing ID numbers are rewritten. This causes content to be assigned to the incorrect placeholder, so it appears to change position. ID numbers should be preserved during the application of layouts to prevent this bug.
Josh Balsillie commented
I second this. I even wrote a very descriptive article that identifies the issue and was recommended to post it again here. I'm glad you beat me to it.