Mini Chart Bug?? Help please

[#1]

I have a straight table, using 2 dimensions and a simple expression SUM(Value) shown as a mini chart month by month

Everything seems fine until i look closely, for some reason, one of the mini charts contains 3 lines, one for it's row, and one for each of the 2 below it... Bizzarre!?

Has anyone else come accross this, is it something i've done? I've started from scratch only bringing in the 4 fields i need into a single table just in case anything else was causing it and have got the same result.

Also, when i produce the same soft of thing in a pivot table, it looks fine. But i dont want a pivot table, i want the mini chart 😞

Here's a picture of what's going wrong, look at row 4.

Very strange.

HELP!

[#2]

Actually, if you leave the concatenated dimension in (hide the column) then add the two original dimensions back, it works perfectly! Still seems odd that it didnt in the first place.