Disabled RAs from default router not working across all interfaces

Issue

We're trying to disable IPv6 router advertisements from the default router across all interfaces. In sysctl.conf, there is a line that says:

net.ipv6.conf.all.accept_ra_defrtr = 0

I was under the impression that "all" meant all interfaces, but it's not actually disabling RA's. For example, if I do a

cat /proc/sys/net/ipv6/conf/all/accept_ra_defrtr

0 is returned, which is fine. However, if I do a

cat /proc/sys/net/ipv6/conf/bond0/accept_ra_defrtr

1 is returned.