This update fixes a regression which was significant enough that it was decided to backport to the release branch.
Bug fixed
#6250 added support for float64 durations in vttablet's yaml configuration. The change introduced a regression where the heartbeat interval unit was changed to seconds, but the conversion was not correspondingly changed. In other words, a heartbeat interval of 1s would have resulted in a value of 1000s instead. The net effect is that healthy replicas would be reported as heavily lagged.
This issue affects only those who enable heartbeats.
This regression as merged into https://github.com/vitessio/vitess/releases/tag/v6.0.20-20200617.
#6359 fixes #6356