Head observation labels don't show correct values in transient mode

[CGoudswaard]

By default the Head Observation labels appear to be somewhat randomly selected and change depending on zoom level in transient mode.

The fix i've found is to apply rule based labeling with the following filter

@map_start_time <= "datetime_end" and "datetime_start" <= @map_end_time

Manually applying this filter after each computation is tedious, perhaps it is possible to automatically apply a similar filter to the layer when creating it in transient mode.