Modules with many interface blocks take a long time to compile

I'm compiling a fortran project using Intel Fortran compiler 16 under RHEL Linux 6.8. In this project, I have several module files containing only interface blocks of routines (I'm using these similar to the function of C/C++ header files), and I add USE statements with ONLY clauses for the appropriate routines in the routines I'm calling them from in order to circumvent the error 8055 (The procedure has a dummy argument that has the ALLOCATABLE, ASYNCHRONOUS, OPTIONAL, POINTER, TARGET, VALUE or VOLATILE attribute. Required explicit interface is missing from original source).

Now when I have a module file declaring, say, ~80 interfaces to subroutines, this file takes a very long time to compile compared to, e.g., a whole module file with several thousands of lines of 'ordinary' source code. It seems to help a little bit to split them up into several submodules inside of the module file like this (as opposed to having all interface in one module block):

MODULE MY_MOD_1
   INTERFACE
      ...
   END INTERFACE
END MODULE MY_MOD_1

MODULE MY_MOD_2
   INTERFACE
      ...
   END INTERFACE
END MODULE MY_MOD_2
...

MODULE MY_MAIN_MOD
   USE MY_MOD_1
   USE MY_MOD_2
   ...
END MODULE MY_MAIN_MOD

My questions are now:
Why does it take so long to compile simple interface blocks (should I file a bug report?) and is there any way to speed that procedure up?

N.B.: I know the 'proper' solution would be to move the routines requiring interfaces to module files but that is, unfortunately, not possible as that would mean grave changes to the structure of the historically grown code base