Firefox Voucher bug?

[Gohran]

I am experiencing a very strange bug in Firefox. The vouchers time for validity, expiration, etc. is showing as an integer instead of a date. In Chrome, however, everything looks great. I wonder if somebody else could confirm that this is not just my system.

[fabian]

Cannot reproduce
Firefox 59 (Linux), Addons: HTTPS Everywhere, ublock origin, foxyproxy

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OPNsense 18.1.5-amd64
FreeBSD 11.1-RELEASE-p8
LibreSSL 2.6.4