The problem was:
I define two modules with the same name IssuePatch
so the first module overwrites the second but
Issue.send :include, IssuePatch
still exists in 2 places (for each plugin) and the same module (doesn't matter which one overwrites the other) so the same module were included 2 times and the same alias_method_chain were called 2 times.
The solution: I just add separate module for each plugin and included them like this:
Issue.send :include, FirstPlugin::IssuePatch
Issue.send :include, SecondPlugin::IssuePatch