What's wrong with this formula?

Hi,
I have a standard filter applied to one or more columns and need to count the resulting visible cells in another column that equal a certain value. In Excel this can be done with the following formula:-

=SUMPRODUCT(SUBTOTAL(3,OFFSET(BH10,ROW(BH10:BH1000)-ROW(BH10),0))*(BH10:BH1000=“T”))

This counts the number of visible cells in column BH that equal “T”. The result happens to be 29, however when I use this same formula in Calc on the same spreadsheet I get 270538 !. Anyone know what could be going on here?. Thanks. p.s. I should add that it makes no difference if the formula is entered as an array formula or not.
LO 4.4.6.3 on Linux.

Please submit a bug report at https://bugs.documentfoundation.org/
Apparently Excel treats an array of OFFSET() results differently if it occurs as an argument to SUBTOTAL().

Thanks for the suggestion and link to Bugzilla. Bit of a delay but bug report now submitted.