It clearly looks like a bug, it bugs me for sure, but it is probably very friendly to everybody else - nobody other than you and me seems to care...
I was afraid, when I posted, that I'll get at least 50 answers telling me that I'm the only one to not know about it. I guess everybody is captivated by threads like MOTD, no time and energy left.

>>>I also get an empty date if I issue
>>>GOMONTH( 12/31/00, -2976 )
>>>This would take it into 1952.
>>
>>No, it will take it to 1652.
>Actually
>GoMonth( {12/31/00}, -2975 ) && returns {01/31/1753}
>and
>GoMonth( {12/31/00}, -2976 ) && returns empty date s/b {12/31/52}
>
>But
>GoMonth( {12/31/53}, -1 ) && returns {12/31/52}