The code handling shift and fn was changed in h-i-m-f-2.1.56 which is in SDK1.2, so presumably is also in PR1.2 itself. I cannot tell for sure, but it seems to me that it works a little better then previously, but still not as expected. If someone knows how to test this in the SDK, I'll be happy for advice.

The new code appears to handle sticky shift, locked shift and pressed shift as three different shifts, and only sticky shift gives the option of four characters per key.