What?
Again?
Come on mate!
You can't be serious (actually you are)
I've never called this medal "mystery medal".
Nothing mystical about it.
The piece was made between 1930-1960.
That's it.
We don't have anything for more precise attribution.
Except...
The BOX.
Remember the box?
This was a real deal.
For you it was
"The case seems to be made of Bakelite like those postwar Rising Suns and Sacred Treasure cases, but with a lot more heft. The hinge is a pin running through the back of the case, not like the lacquered cases. I believe it is of aluminum. Different style hasp, that was used on some later awards (post-1956) - I'm only guessing, but this might be an actual war-era award, but must be pre-1956 before the Red Cross adopted separate silver and gold awards around that time."
And the box is still wonder-mystical-box.
P.S. Thanks for marked rosette photo mate! Nice specimen you've got! Congrats!