Here is one of the ways that can cause these messages

junk.pm

package junk;
use strict;
use warnings;
use Exporter qw[ import ];

our @ISA = 'Exporter';
our @EXPORT_OK = qw[ test test2 ];

sub test{ print 'test' }
sub test2{ print 'test2'; goto &test;  }

1;
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junk.pl

#! perl -slw
use strict;
use junk qw[ test test2 ];

test;
test2;
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Profiling output

C:\test>perl -d:DProf junk.pl
test
test2
test

C:\test>dprofpp tmon.out
junk::test has 1 unstacked calls in outer
junk::test2 has -1 unstacked calls in outer
Total Elapsed Time = 0.014928 Seconds
  User+System Time = 0.015928 Seconds
Exclusive Times
%Time ExclSec CumulS #Calls sec/call Csec/c  Name
 0.00       - -0.000      1        -      -  strict::bits
 0.00       - -0.000      1        -      -  warnings::BEGIN
 0.00       - -0.000      1        -      -  warnings::import
 0.00       - -0.000      2        -      -  junk::test
 0.00       - -0.000      2        -      -  strict::import
 0.00       - -0.000      2        -      -  Exporter::import
 0.00       - -0.000      1        -      -  junk::test2
 0.00       - -0.000      3        -      -  junk::BEGIN
 0.00       - -0.000      2        -      -  main::BEGIN
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The use of the "magic" goto in subroutine test2(), goto &test, is an optimisation that is sometimes usefully used by packages. It's effect is to transfer control from the first subroutine to the second in such a way as to ensure that when the second subroutine returns, control is transferred directly back to the original caller, rather than back through the first subroutine. This can be used to implement a form of the 'tail call optimisation'.

As dprof tracks and logs entry and exits to subroutines and then tries to match them when calculating the timing information, this one-way transfer of control confuses it's matching process and the warnings you see reflect that.

Either ignore the warnings, or use one of the line-by-line profilers which time each line, rather than each subroutine as so do not become confused. They are often more useful, though the profiling process is necessarily much slower.