3rd party macros/plugins for Confluence Cloud are rendered using the Confluence Connect framework.
There are many limitations for Connect macros, especially in the areas of nesting and styling. Atlassian does not implement their own macros using Connect so their “native” macros are not subject to all of these limitations. Therefore, users often mistakenly think that a 3rd party macro is broken with it is actually running into some limitation of Connect.
Here is a list of some of the nesting issues that we have encountered with Connect macros: