I do not think this issue is about disk caching, but the fact that the data being saved is a false (boolean).
Looks to me that there is an issue elsewhere, and turning off disk caching doesn't fix the issue, but just prevents the error. This issue only started after the core updated to 8.1.
I haven't had a chance to actually debug this issue further, but what I have seen, I don't think turning off disk caching is the actual solution to this issue.