[snbzk]

Thanks for your efforts, Nagoyankee. While the issue doesn't seem to have been totally resolved, I'll take your advice anyway and only use の in the subject.

Just for the sake of argument, I found the relevant point in the book where I originally heard about the phenomenon:

の
5. Used to replace が to indicate the subject of a clause modifying a noun.
これは坂本さんの描いた油絵です。
昨日あなたの話していたレストランはどこですか。