Bus pin assignment being ignored by fitter

I have a 10-bit wide output bus: out[9..0]. I assigned each output wire to a pin using the pin placement tool. The Live I/O check passes and there are no errors for the pin assignments. However, it seems like the pin assignment for out[9] is ignored. The fitter gives a warning during compilation that out[9] has not been assigned to an exact location on the device (although it has) followed by another warning that out[9] was not found in the design. In the PIN_OUT file I see that the I/O pin to which I assigned out[9] is RESERVED INPUT WITH WEAK PULL_UP (the default assignment for unconnected I/Os) and out[9] is assigned to another pin which I did not assign to anything.

I re-assigned out[9] to another I/O and it's again ignored. The pin placement tool/planner has the right (my) I/O assignment and the symbol in the top-level bdf file is also updated to reflect the right I/O assignment. However during compilation I get the same warnings pertaining to out[9] and the PIN_OUT file again assigns out[9] to a different I/O pin and thinks that the I/O pin that I had assigned to it is an unused I/O.

Thanks,

Kunal.