"free tier" account's CodeBuild stops after 45min

I am on a "free tier" AWS account, and I'm attempting to use CodeBuild for an openWRT CI build. The source code is extracted from bitbucket just fine, and openWRT system requirements are also loaded according to the buildspec.yml, and the openWRT build seems to start and get underway correctly without errors. However the build always fails due to a timeout after 45min and 20 or so seconds.

I have edited the build environment to set the timeout to 4 hours, as well as the associated service role's maximum session duration to 4 hours. I have saved these values, and they appear set when I review the settings. However after these values are set and confirmed, when the build is attempted it fails due to timeout at the 45 min mark! I then review the "build details" of the failed build and the environment setting in this window shows the timeout as 45m! Somehow the build timeout I set is being overridden, is there a way to correct this?