hentaiixxx on "HTTP ERROR 500 for Publish / Update Posts but Not For Pages"

After upgrading to wordpress 4.5,

getting "HTTP ERROR 500",
whenever I Publish / Update any "Posts",

the odd thing is that it only happen to "POSTS",
the "PAGES" are fine,

things I've done to troubleshoot,

1.) deactivated all plugins (HTTP ERROR 500)
2.) re-save "permalink" settings (HTTP ERROR 500)
3.) tried saving permalinks to id and publish / update posts (HTTP ERROR 500)

calling all wordpress gurus,
what other suggestions can you guys suggest me to fix this problem?

Thanks