You can see with:
jpm janet temple-loader-repro\init.janet
that the code is valid, but Janet++ shows problem:
could not find module /templates/index:
templates/index.jimage
templates/index.janet
templates/index/init.janet
templates/index.dll
temple-loader-repro/templates/index.janet
temple-loader-repro/templates/index.janet
temple-loader-repro/templates/index.janet
test/templates/index.janet
test/templates/index.janet
test/templates/index.janet