Normally, if you configure a plan variable with a name like "myVariable", it will be accessed as "${bamboo_myVariable}" in a file script.
However, if the plan variable is given a name that already starts with keyword "bamboo", so for example "bambooFooBar", it should be accessible as "${bamboo_bambooFooBar}" in a file script, but instead Bamboo gets confused and doesn't add any prefix in the variable substitution phase, so it comes out as "${bambooFooBar}". This in clear in the logs in the variable substituion were it shows:
bamboo_myVariable=x
bambooFooBar=y
bamboo_yetAnotherVar=z
However, for inline scripts (not in an external file), where prefix "bamboo." rather than "bamboo_" is used, the normal substitution of "bambooFooBar" to ${bamboo.bambooFooBar} seems to work fine.
Is there a bug ticket already for this issue? I wasn't able to find one in a quick search.