Animated markers missing when using pre1970 dates in TimestampedGeoJson

Animated markers missing when using pre1970 dates in TimestampedGeoJson. I understand this functionality from Leaflet.TimeDimension, but had thought this issue was fixed there (Merged pull request: https://github.com/socib/Leaflet.TimeDimension/pull/91).

Please add a code sample or a nbviewer link, copy-pastable if possible

import folium
from folium.plugins import TimestampedGeoJson

# Post-1970 timestamps: 1970-01-02, 1970-01-03, 1970-01-04
milliseconds_per_day = 1000 * 60 * 60 * 24
post_1970_timestamps=[1*milliseconds_per_day, 2*milliseconds_per_day, 3*milliseconds_per_day]
# Pre-1970 timestamps: 1969-12-29, 1969-12-30, 1969-12-31
pre_1970_timestamps=[0-time for time in post_1970_timestamps]
# Ensure pre_1970_timestamps are in ascending order:
pre_1970_timestamps.reverse()

m = folium.Map(location=[0,0],zoom_start=2)
ts=TimestampedGeoJson({
     'type': 'FeatureCollection',
     'features': [
       {
         'type': 'Feature',
         'geometry': {
           'type': 'LineString',
           'coordinates': [[-70,-25],[-70,35],[70,35]],
           },
         'properties': {
            # Dates shown in time slider controls, but no markers displayed on map
            # Contrast behaviour when times read from post_1970_timestamps list:
            # - animated markers shown on map as per example
            'times': pre_1970_timestamps
            #'times': post_1970_timestamps 
           }
         }
       ]
     })
ts.add_to(m)
m

Problem description

No markers shown on maps using TimestampedGeoJson with dates pre 1970 (as held in pre_1970_timestamps list)

Expected Output

Animated markers as per the TimestampedGeoJson with post_1970_timestamps

Output of folium.__version__

0.10.0

Bắt đầu từ điểm vào folium.plugins.TimestampedGeoJson và so sánh cấu hình Leaflet.TimeDimension được tạo cho các timestamp âm với mẫu được cung cấp sau năm 1970. Tái hiện ví dụ, theo dõi cách các giá trị trước năm 1970 đi tới animation và xác minh rằng các marker động xuất hiện cho cả hai phạm vi timestamp.