Try using Carp::Always to get a backtrace at the point of the warning and walk your way through the subroutine calls from the source code of your application to the offending line of Net::SSLeay.

Using integrated debugger to set a breakpoint at the starting line of backtrace (one you found it) (f yourprogram.pl, b linenumber, c) and examine your data (x $variable, V, y) can also shed light on the situation. See also break on warning in debugger.