Include issue with absolute and relative path result in conflicting IDs

Description of Issue

I think include does not work as expected when include relative and absolute path

Setup

• File salt/bug/init.sls :

include:
  - .bug
  - .include

• File salt/bug/bug.sls:

bug:
  test.succeed_without_changes:
    - name: bug

• File salt/bug/include.sls:

include:
  - salt/bug/bug

include_bug:
  test.succeed_without_changes:
    - name: include_bug
    - require:
      - id: bug

Steps to Reproduce Issue

$ salt-call state.apply salt/bug
local:
    Data failed to compile:
----------
    Detected conflicting IDs, SLS IDs need to be globally unique.
    The conflicting ID is 'bug' and is found in SLS 'base:salt/bug.bug' and SLS 'base:salt/bug/bug'

Now if I replace with full path in salt/bug/init.sls:

include:
  - salt/bug/bug
  - salt/bug/include

$ salt-call state.apply salt/bug
local:
----------
          ID: bug
    Function: test.succeed_without_changes
      Result: True
     Comment: Success!
     Started: 10:20:43.032602
    Duration: 0.0 ms
     Changes:
----------
          ID: include_bug
    Function: test.succeed_without_changes
      Result: True
     Comment: Success!
     Started: 10:20:43.033596
    Duration: 0.0 ms
     Changes:

Summary for local
------------
Succeeded: 2
Failed:    0
------------

Versions Report

Salt Version:
           Salt: 2019.2.0

Dependency Versions:
           cffi: 1.11.5
       cherrypy: 17.4.1
       dateutil: 2.7.5
      docker-py: Not Installed
          gitdb: 2.0.5
      gitpython: 2.1.10
          ioflo: Not Installed
         Jinja2: 2.10
        libgit2: 0.28.2
        libnacl: 1.6.1
       M2Crypto: Not Installed
           Mako: 1.0.7
   msgpack-pure: Not Installed
 msgpack-python: 0.5.6
   mysql-python: Not Installed
      pycparser: 2.17
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: 0.28.2
         Python: 3.5.4 (v3.5.4:3f56838, Aug  8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)]
   python-gnupg: 0.4.3
         PyYAML: 3.13
          PyZMQ: 17.1.2
           RAET: Not Installed
          smmap: 2.0.5
        timelib: 0.2.4
        Tornado: 4.5.3
            ZMQ: 4.2.5

System Versions:
           dist:
         locale: cp1252
        machine: AMD64
        release: 10
         system: Windows
        version: 10 10.0.18362 SP0 Multiprocessor Free