As usual while waiting for the next release - don't forget to check the nightly builds in the forum.
Then why don't you turn it off until it's fixed?
if (strVal != _T("\"") + exe + _T("\" ") + batchbuildargs + _T(" --build \"%1\""))
"D:\Devel\CodeBlocks_Devel\codeblocks.exe" -na -nd -ns --batch-build-notify --build "%1"
"D:\Devel\CodeBlocks_Devel\codeblocks.exe" /na /nd /ns --build "%1"
Update and try now, please [...]
... it worked either way because I hadn't turned on "check associations", lol.......