I can't reproduce this issue on my local installation, so I suspect that maybe there is a problem in conflict with your WordPress theme. Sometimes theme can override Toolset hooks, to build their own features.
Can you please check does the problem still exist if you activate default WP theme (i.e. Twenty Fifteen)?
For sure! I'll test it out and let you know. It hasn't happened again since this last time. I just saved the layout again and the problem went away. Let's hope it doesn't come back. I'll close this thread for now as the issue hasn't resurfaced. Thank you.