While we did not find it in our testing of Enketo 6.1.0 prior to releasing it for use with KoboToolbox, this is in fact a known issue with Enketo 6.1.0 that was fixed in Enketo 6.2.0. However, we have not yet done any testing on Enketo 6.2.0, so we will roll back to the previous version again.
Thanks for reporting this problem.