I couldn't find a similar issue and it seems to me that this should be a bug.

I have downloaded OpenBLAS-0.3.24-x64 from sourceforge (https://sourceforge.net/projects/openblas/files/v0.3.24) and used it to compile openCV. After linking my own application against opencv, it looks for lipopenblas.exp.dll, which does not exist, as the dll that is shipped in the sourceforge archive is (correctly) called libopenblas.dll.

On further inspection, I have seen that dumpbin /all libopenblas.lib contains

RAW DATA #6
  00000000: 6C 69 62 6F 70 65 6E 62 6C 61 73 2E 65 78 70 2E  libopenblas.exp.
  00000010: 64 6C 6C 00                                      dll.

so it looks to me that the .lib file incorrectly specifies a dll name that is incorrect.

The only mentioning of this in any way I could find was https://www.itworks.hu/running-whisper-cpp-on-windows/ which contains instructions to just rename the DLL