diff --git a/cmake/compiler_flags/Cray_Fortran.cmake b/cmake/compiler_flags/Cray_Fortran.cmake
index 95f15230..65c0d44d 100644
--- a/cmake/compiler_flags/Cray_Fortran.cmake
+++ b/cmake/compiler_flags/Cray_Fortran.cmake
@@ -8,8 +8,20 @@
 
 # -emf activates .mods and uses lower case
 # -rmoid produces a listing file
-set( CMAKE_Fortran_FLAGS_RELEASE        "-emf -rmoid -N 1023 -O3 -hfp3 -hscalar3 -hvector3 -DNDEBUG"                    CACHE STRING "Release Fortran flags"                 FORCE )
-set( CMAKE_Fortran_FLAGS_RELWITHDEBINFO "-emf -rmoid -N 1023 -O2 -hfp1 -g -DNDEBUG"                                     CACHE STRING "Release-with-debug-info Fortran flags" FORCE )
-set( CMAKE_Fortran_FLAGS_PRODUCTION     "-emf -rmoid -N 1023 -O2 -hfp1 -g"                                              CACHE STRING "Production Fortran flags"              FORCE )
-set( CMAKE_Fortran_FLAGS_BIT            "-emf -rmoid -N 1023 -O2 -hfp1 -g -hflex_mp=conservative -hadd_paren -DNDEBUG"  CACHE STRING "Bit-reproducible Fortran flags"        FORCE )
-set( CMAKE_Fortran_FLAGS_DEBUG          "-emf -rmoid -N 1023 -O0 -g"                                                    CACHE STRING "Debug Fortran flags"                   FORCE )
+
+if( CMAKE_Fortran_COMPILER_VERSION VERSION_GREATER_EQUAL 18.0.0 AND CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 20.0.0 )
+    # Unfortunately, CCE 18 and 19 incurred a bug in the lower-casing of
+    # submodule .smod files, leading to incomplete lower-casing of the output
+    # file name, e.g., `parent_mod.sUB_MOD.smod`.
+    # This is supposedly fixed in CCE20, but we have to switch off the use of
+    # lowr-casing, thus only using the `-em` option for versions in-between.
+    set( _crayftn_mod_options "-em" )
+else()
+    set( _crayftn_mod_options "-emf" )
+endif()
+
+set( CMAKE_Fortran_FLAGS_RELEASE        "${_crayftn_mod_options} -rmoid -N 1023 -O3 -hfp3 -hscalar3 -hvector3 -DNDEBUG"                    CACHE STRING "Release Fortran flags"                 FORCE )
+set( CMAKE_Fortran_FLAGS_RELWITHDEBINFO "${_crayftn_mod_options} -rmoid -N 1023 -O2 -hfp1 -g -DNDEBUG"                                     CACHE STRING "Release-with-debug-info Fortran flags" FORCE )
+set( CMAKE_Fortran_FLAGS_PRODUCTION     "${_crayftn_mod_options} -rmoid -N 1023 -O2 -hfp1 -g"                                              CACHE STRING "Production Fortran flags"              FORCE )
+set( CMAKE_Fortran_FLAGS_BIT            "${_crayftn_mod_options} -rmoid -N 1023 -O2 -hfp1 -g -hflex_mp=conservative -hadd_paren -DNDEBUG"  CACHE STRING "Bit-reproducible Fortran flags"        FORCE )
+set( CMAKE_Fortran_FLAGS_DEBUG          "${_crayftn_mod_options} -rmoid -N 1023 -O0 -g"                                                    CACHE STRING "Debug Fortran flags"                   FORCE )