Format Strings don't work on a SSAS Model with Calculation Group(s)

Hi folks, I have the same issue here, and I have discovered something that might help in the struggle. The thing is, in my case, I find the following: When Calc groups are added to the model, yes, the measures become variant. But this is not an issue by itself!... If all FormatStringExpression of all Calculation Items are empty, then the behaviour of measures is unchanged (at least in my testings) - the usual format strings of normal measures are properly shown in graphs, business as usual, all happy If afterwards, I add just one FormatStringExpression to ANY of the Calculation Items, (including SELECTEDMEASUREFORMATSTRING () or any other), then the bug arises and graphs in PowerBI do not respect their source formatting (matrix is OK as you have reported) So in my case, it looks that the problem does not come from just 1500, or from adding calculation groups, but from adding a single FormatStringExpression to the model. Therefore, in my case so far I am able to add Calculation Groups and Items without and issue to an existing model (phew!), but not use the custom format feature. I hope this helps shed some light, and yes, Microsoft should solve this!