We have strict work-from-home policies, which only apply to some of our staff. Which no one follows. But for some positions, it just doesn't make sense.
A few years back, we hired someone that immediately took a month long vacation for wedding/honeymoon, then came back to work to announce that she was moving to another coast and working remotely. She decided that the above pertained to her, although our company policies said otherwise. Lots of calls with her at the pool, or having to wait until after yoga to be available for a call. But that started many of our work-from-home employees to do the same. (Thankfully, we finally got rid of her - for cause, because she actually didn't do a good job when she deigned to work - but it took a long time, and the damage stayed behind.)
It is a huge problem now. Those in the office might need information from a work-from-home person, but can't get it on a timely basis. Or it takes 10 emails spread out over 3 days to resolve an issue that would take 10 minutes face to face. And those that work-from-home will ask for and/or provide information nights, weekends, vacations, and expect immediate turnaround. So now there's an imbalance in workloads. Those that work from home have flexibility during the week, and don't feel the need to work 40 hours if they get their work done. But those that are in the office 9-5 all week are now expected to be responsive off hours on top of the 40+ hour work week, so it is adding hours to in-office employees.