Ground plane not connected

I have a 8 layer pcb design with two continuous dedicated digital gnd planes sandwiching the high speed data signals. They were assigned as negative planes and by mistake got connected to a sheild gnd signal (that is connected to mounting holes). This didn't come up as a error in altium as there are other digital ground polygons or planes that connect all the gnds on the board and the two planes were mainly for the high speed signals.
This means there is no issue with the functionality of the board but I would like to know if it makes sense to rerun the board with the planes connected.
Presently they are like big floating polygons surrounding the high speed signals.