See wikipedia.
"steep learning curve" is a buzz-phrase that doesn't have any actual meaning. It used to mean that you'd make quick progress. "Over time, the misapprehension has emerged that a "steep" learning curve means that something requires a great deal of effort to learn..."
Conclusion: people who use the phrase don't know that it's unclear. You should get details from them on what specific things are hard to learn and get past the buzz-phrases and platitudes.