#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11129253
use warnings;

local $_ = <<END;

Point 1.3.4: A piece of text.

Point 1.3.5: A piece of text.

Point 1.3.6: Another piece of text. Point 1.3.6: For some reason this piece of text isn't finished yet.

Point 1.3.6: In fact, this piece of text even broke into a new line.

Point 1.3.7: Finally, a new piece of text.

END

my @parts;
push @parts, $& while / (Point\s[\d.]+:) .*? (?=Point|\z) (?!\1) /gsx;

use Data::Dump 'dd'; dd \@parts;