addTime with negative values

Hello,

I’m having an issue where addTime cannot subtract negative values. Here is my code:
{{tl_update_date.toDate().addHours(serverconnect_current_user.data.current_user_query.t_delta)}}
when t_delta =< 0, I get the intended result, but when the value is negative, I get this:
0NaN-aN-aN aN:aN:aN

I’ve done some research in the forum where this was met before but somehow fixed itself. @Teodor @patrick , I’d appreciate the help. If I convert the value to timestamp, nothing is displayed at all.

Thanks!