I've committed to 3.6.1 and 3.7, but I'm not convinced that the problem is worth the risk of changing the behaviour in 2.7.14 and 3.5.3.

Considering we kept forgetting to commit this for so long and largely got away with it, I assume there aren't hundreds of people being bitten by this on a daily basis. There are also other ways to work around the problems that have occurred (editing and resaving the values in Registry Editor should suffice, and the attached nullcheck scripts can help find the problematic values).

So while 2.7 and 3.5 will continue to not trim REG_SZ values at the first embedded null, I think that's best for preserving the ability of users to upgrade easily between microversions (particularly for 2.7).