Google Chrome Network Developer Tools - Form Data is missing from headers tabs on most sites
Good news, a fix has been commited to the repo, however it won't probably make it to v63 release, so we will likely have to wait for v64... The best way to get it ASAP is to get dev/beta version of Chrome and wait till it arrives there. I will update this once it arrives into the public release of Chrome.
Update: It appears that this has been merged to v63 release, so it should be out very soon for all users.