Test:
Joomla 3.4.8, 3.5.0beta, Protostar

• Create a module of type Custom.
  Enter some text.
  Enter a position like "somewhere".
  Select module style "html5".
  Set "Show Title": SHOW
  Save and close.

• Create 2nd module of type Custom.
  Enter in editor

{loadposition somewhere}

Select an existing template position, e.g. "banner".
Set "Prepare Content": YES
Set "Show Title": HIDE
Select module style "none".
Save and close.

• Select 2nd module (check). Click button Duplicate to create a copy. Publish 3rd module.

See frontend:
2 headlines in one module.
The whole HTML from module style is duplicated.

Cache is explicitely disabled in module 1.
No Joomla cache or cache plugin active.
same behavior when 3rd module has another position than 2nd