60 nanoseconds ~= 60*30cm ~= 18 meters.
I kind of doubt that lousy connection would make the timing signal arrive 18 meters late. That requires the signal being re-sent and arriving only on second, third, and so on attempt.
That's 18 meters for light in a vacuum. GPS receivers and lousy connections are not made out of vacuums. Translating into meters doesn't help us all that much when we are considering hardware faults like this.
18 meters of air, ~12 meters of glass, ~36 meters of going through glass instead of air, and a lot of meters for going through faster glass rather than slower glass when connection is tightened (and don't think of the signal bouncing at an angle and arriving slower, that's not how fibre optics works). If they have a long glass cable, you can be certain that delay has to be actually measured because speed is temperature dependent.
The point of the conversion from nanoseconds to meters is to have some sort of intuitive reference just how much behind the signal must get via lousy connection.
A mundane cause for a surprising result. Consider this unconfirmed for now, however unsurprising it sounds.
Source: Science/AAAS