Mixed datetime formats at [HangFire].[State], Data column

question
1

Hi all,

I recently joined a project that is using hangfire 1.6.20.
We are having some problems with our code, and I decided to enable hangfire dashboards to help me check what is gong on.
I am getting some exceptions if I move to the 2nd page of the failures. When debugging I find out that the reason is due to different datetime formats in my database:

The query I ran:

select top 1000 s.data from [HangFire].[Job] j
	join [HangFire].[State] s on j.StateId = s.Id
where j.StateName = 'Failed'

The resuts

{"FailedAt":"2022-11-30T15:34:13.7419289Z","ExceptionType":"..."}
{"FailedAt":"1669822299229","ExceptionType":"..."}

The 1st row works, the 2nd not. The most recent records looked all good and using the 1st line format, but old ones not.

Any idea what caused this difference in datetime format? Any .net/DI registration that affects hangfire? Maybe json serialization options?

Thank you