Hello,
I've had this issue before i don't know what fixed it and it's doing it again.
I have iOS devices and I've installed a profile and then the Safe Browser but when I make any changes to the policy they don't take affect, it just stays in the status "In Progress", it's been like it for about couple of days now.
If I try to sync the iOS device on Safe Browser it sync's fine so they are talking to the server but still doesn't make any changes, see attached, it's been working fine.
I had a patch update and changed the policy to a "non inherited" policy, originally it was inherited it was but that's the only changes that I can think of.
I'm also on KSC version 10.5.1781.