Saving cube with Proleptic Datetime changes time axis

[felixcremer]

When I am saving a data cube with a nanosecond resolution to disk this is some how scrambled and I get a date time back with strange values.
I can't use the prefer_datetime keyword in the Cube constructor but I would have expected that it would recognize it automatically.

julia> path = "/home/fcremer/Documents/EOPF.jl/data/S1A_IW_GRDH_1SDV_20250626T053421_20250626T053446_059813_076DB6_D372.zarr/S01SIWGRD_20250626T053421_0025_A342_D372_076DB6_VH/measurements/"
"/home/fcremer/Documents/EOPF.jl/data/S1A_IW_GRDH_1SDV_20250626T053421_20250626T053446_059813_076DB6_D372.zarr/S01SIWGRD_20250626T053421_0025_A342_D372_076DB6_VH/measurements/"

julia> zopen(path)^C

julia> c = Cube(path)
┌ 26533×16668 YAXArray{UInt16, 2} measurement data set for GRD IW ┐
├─────────────────────────────────────────────────────────────────┴─────────────────────────────────────────── dims ┐
  ↓ ground_range Sampled{Float64} 0.0:10.0:265320.0 ForwardOrdered Regular Points,
  → azimuth_time Sampled{CFTime.DateTimeProlepticGregorian{CFTime.Period{Int64, Val{1}(), Val{-9}()}, Val{(2025, 6, 26, 5, 34, 21, 819, 152)}()}} [DateTimeProlepticGregorian(2025-06-26T05:34:21.819152), …, DateTimeProlepticGregorian(2025-06-26T05:34:46.817343)] ForwardOrdered Irregular Points
├───────────────────────────────────────────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any} with 5 entries:
  "dtype"       => "<u2"
  "coordinates" => "line pixel"
  "name"        => "grd"
  "long_name"   => "measurement data set for GRD IW"
  "_eopf_attrs" => Dict{String, Any}("dtype"=>"<u2", "coordinates"=>Any["azimuth_time", "line", "pixel", "ground_ran…
├──────────────────────────────────────────────────────────────────────────────────────────────────── loaded lazily ┤
  data size: 843.53 MB
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

julia> subc = c[azimuth_time=1:100, ground_range=1:100]
┌ 100×100 YAXArray{UInt16, 2} measurement data set for GRD IW ┐
├─────────────────────────────────────────────────────────────┴─────────────────────────────────────────────── dims ┐
  ↓ ground_range Sampled{Float64} 0.0:10.0:990.0 ForwardOrdered Regular Points,
  → azimuth_time Sampled{CFTime.DateTimeProlepticGregorian{CFTime.Period{Int64, Val{1}(), Val{-9}()}, Val{(2025, 6, 26, 5, 34, 21, 819, 152)}()}} [DateTimeProlepticGregorian(2025-06-26T05:34:21.819152), …, DateTimeProlepticGregorian(2025-06-26T05:34:21.967638284)] ForwardOrdered Irregular Points
├───────────────────────────────────────────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any} with 5 entries:
  "dtype"       => "<u2"
  "coordinates" => "line pixel"
  "name"        => "grd"
  "long_name"   => "measurement data set for GRD IW"
  "_eopf_attrs" => Dict{String, Any}("dtype"=>"<u2", "coordinates"=>Any["azimuth_time", "line", "pixel", "ground_ran…
├──────────────────────────────────────────────────────────────────────────────────────────────────── loaded lazily ┤
  data size: 19.53 KB
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

julia> subc_saved = savecube(subc, "testdatasub.zarr")
┌ 100×100 YAXArray{UInt16, 2} measurement data set for GRD IW ┐
├─────────────────────────────────────────────────────────────┴─────────────────────────────────────────────── dims ┐
  ↓ ground_range Sampled{Float64} 0.0:10.0:990.0 ForwardOrdered Regular Points,
  → azimuth_time Sampled{CFTime.DateTimeProlepticGregorian{CFTime.Period{Int64, Val{1}(), Val{-9}()}, Val{(2025, 6, 26, 5, 34, 21, 819, 152)}()}} [DateTimeProlepticGregorian(2025-06-26T05:34:21.819152), …, DateTimeProlepticGregorian(2025-06-26T05:34:21.967638284)] ForwardOrdered Irregular Points
├───────────────────────────────────────────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any} with 5 entries:
  "dtype"       => "<u2"
  "coordinates" => "line pixel"
  "name"        => "grd"
  "long_name"   => "measurement data set for GRD IW"
  "_eopf_attrs" => Dict{String, Any}("dtype"=>"<u2", "coordinates"=>Any["azimuth_time", "line", "pixel", "ground_ran…
├──────────────────────────────────────────────────────────────────────────────────────────────────── loaded lazily ┤
  data size: 19.53 KB
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘

julia> subc_loaded = Cube("testdatasub.zarr/")
┌ 100×100 YAXArray{UInt16, 2} measurement data set for GRD IW ┐
├─────────────────────────────────────────────────────────────┴─────────────────────────────────────────────── dims ┐
  ↓ ground_range Sampled{Float64} 0.0:10.0:990.0 ForwardOrdered Regular Points,
  → azimuth_time Sampled{DateTime} [DateTime("45487464-11-02T23:32:31.872"), …, DateTime("45487464-11-04T16:47:18.272")] ForwardOrdered Irregular Points
├───────────────────────────────────────────────────────────────────────────────────────────────────────── metadata ┤
  Dict{String, Any} with 6 entries:
  "dtype"       => "<u2"
  "coordinates" => "line pixel"
  "name"        => "grd"
  "long_name"   => "measurement data set for GRD IW"
  "_eopf_attrs" => Dict{String, Any}("dtype"=>"<u2", "coordinates"=>Any["azimuth_time", "line", "pixel", "ground_ran…
  "_FillValue"  => 0xffff
├──────────────────────────────────────────────────────────────────────────────────────────────────── loaded lazily ┤
  data size: 19.53 KB
└───────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘