XF 1.5 xf_session cookie expiry set to 1969

[valdet]

I noticed the expiry date of the xf_session cookie is set to "expire" on 31 Dec 1969 at 23:59:59, a second before Unix time start.



I find this odd, is this expected behavior ? If not, what could this impact ?

We don't have any issues with login or similar, just wanted to check if this standard.

Thanks