Fun With Dates -- Need Help

Greetings GNU/Linux knowledgeable enthusiasts.  Please help me
out on this one.

The ancient Julian calendar transitioned into the modern Gregorian
calendar on Thursday, October 4, 1582.

But, the next day jumped to Friday, October 15, 1582 (I'll allow
you to pursue the historical details).

Let's allow GNU/Linux to explore this transition.

cal --reform gregorian oct 1582

     October 1582   
Su Mo Tu We Th Fr Sa
                1  2
 3  4  5  6  7  8  9
10 11 12 13 14 15 16
17 18 19 20 21 22 23
24 25 26 27 28 29 30
31

This shows Oct 4 to be a Monday and there in no jump.

It's the same with the "date" command:

[~]# date -u -d "now -161543 days"
Mon Oct  4 08:41:04 PM UTC 1582

[~]# date -u -d "now -161542 days"
Tue Oct  5 08:44:43 PM UTC 1582


However, if I use LibreOffice Calc:

Entering -115859 into a date formatted cell gives:

Thursday, October 4, 1582

Entering -115858 gives:

Friday, October 15, 1582

We see the jump and correct day with LO but not with the
GNU/Linux date/cal commands.  What is the problem?  What
am I doing wrong?

I will continue to investigate because I know that none of
you lackeys know what the fuck is going on.

Ha, ha, ha, ha, ha, ha, ha, ha, ha, ha!

Warning: don't try this with Microslop Exhell cause it will
blow up in you face.

Ha, ha, ha, ha, ha, ha, ha, ha, ha, ha!



--
Systemd: solving all the problems that you never knew you had.