Using tribble() to create a tibble with an object of class Period (lubridate) fails. The object is saved as numeric 0. When the same is done with tibble(), everything is fine. See the reprex below.
This might be linked to issue #770 I had reported earlier.
library(tibble)
tribble(~period, lubridate::days(1))
#> # A tibble: 1 x 1
#> period
#> <dbl>
#> 1 0
tibble(period = lubridate::days(1))
#> # A tibble: 1 x 1
#> period
#> <Period>
#> 1 1d 0H 0M 0S
Created on 2020-06-05 by the reprex package (v0.3.0)