https://bugs.winehq.org/show_bug.cgi?id=48180
--- Comment #11 from Alexander Milos apmichalopoulos@outlook.com --- Alright, at long last I have some good news!
Turns out that between the patch for strtod in commit c22af971c287933a137c9fbecc81823812e12b7a and 5.0rc2, there has been one more commit by you containing changes directly relevant to this issue: commit a6734f549fc6f5d0a93364d159519a5d6d0b5f38, which fixes the equivalent wcstod parts. And it turns out that *that* commit is what actually fixes the issue reported here.
As I mentioned yesterday, in the name of preserving my test environment and trying not to change too many unknown variables at once, I kept using the 5.0rc1.c22af971c287933a137c9fbecc81823812e12b7a sources, i.e. up to your first patch of a couple of days ago, because I didn't realize that you've actually created not one but two patches (or at least, a single one but in two different parts and in two different commits). But when I updated to 5.0rc2 yesterday in the process of confirming that reverting 0e183cc3c0d3b6f89f79047cdd71c389afc75073 fixes the issue while using the same save file, as you asked, I inadvertently also updated to a version that completely fixes the issue, revert or no revert.
So, that's that; this bug can be closed as fixed. Thank you for your work, both for creating the two patches and for spending your time trying to fix this issue as well.