Gerrit 3.10.4 has a fix for T338810 https://www.gerritcodereview.com/3.10.html#3104 :
Issue 365889749: Fix timeouts calculation in SshDaemon
ote: All the SSH timeouts have been broken since the merge of Change 274055 released with Gerrit v3.4.* until v3.9.8. This fix makes the timeouts being considered as documented again, which may result in SSH connections being closed prematurely due to the configured timeouts in gerrit.config.