You are passing -v to tar, making it write file names as they are extracted. That’s LOTS of output very fast. It’s possible that Travis can’t handle so much and that “write error” is error from writing to stdout rather than disk.
There are already a few known issues with this, e.g. https://github.com/travis-ci/travis-ci/issues/8189 and https://travis-ci.community/t/characters-in-travis-console-log/ .
Travis is not unique here, either, see e.g. https://stackoverflow.com/questions/37540792/jenkins-script-tar-write-error/38738272 for a similar error with Jenkins.
With the number of files in that archive, it’s possible that this is not a bug at all and you are rather hitting the log size limit!