Error with intchron(c("intimate", "nrcf", "oxa"))

While working on https://github.com/ropensci/c14bazAAR/pull/147 in order to close https://github.com/ropensci/c14bazAAR/issues/115 I tried to extract all databases hold in Intchron. But only `egyptdb` and `sadb` were returned
```R
> intimate <- intchron(c("intimate"))
Error in data.frame(..., check.names = FALSE) :
arguments imply differing number of rows: 2501, 0
> nrcf <- intchron(c("nrcf"))
Error in data.frame(series_type = .x$series_type, purrr::map_dfc(.x$data, :
arguments imply differing number of rows: 1, 0
> oxa <- intchron(c("oxa"))
Error in data.frame(series_type = .x$series_type, purrr::map_dfc(.x$data, :
arguments imply differing number of rows: 1, 0
```
In order to write a c14bazAAR parser, I want to check to what degree the returned fields are different from one db to the next. Thus far, I found that `egyptdb` contains also `dynasty` and `reign`; small background detail.

Would you consider this issue to be somewhere on my side or can you replicate the error? I am running v0.1.0.9000