The breakage with Slamdance is on his left ankle, which you can see in the images below. This problem has been reported several times to the Seibertron.com news staff as well as several Transformers fans on Twitter. Apparently the breakage is caused because the feet are very tight and it's the same plastic material on those parts as Flywheels which are susceptible to stress from the get-go. The figure needs to be handled carefully to avoid the breakage, though it is not clear at this time if even that will prevent breakage.
Here are a handful of twitter posts showing the defect and more reports are coming in as people get them:
https://twitter.com/N0tsofriendly/status/1162089529328701440?s=19
https://twitter.com/UnderscoreZeus/status/1162116742727868417/photo/1
https://twitter.com/KPAutobotX/status/1162140505616068612
Good luck to all of you with your Slamdance! Please let us know if you experience any problems with your Slamdance figure so that we can continue to share this information with other Seibertronians.