I am assuming, but not sure, that you have configured the same microflow as onclick event that you also set as datasource for the grid. If not, even then maybe the next will give some pointers to a solution.
The way set it up the following will happen:
This causes a loop.
Solution: split the microflows in one ACT_ microflow that only does the show page and one DS_ microflow that retrieves the data.
I hope this helps.