Devices lose IPv6 connectivity

[Lilly]

Hello,

so I've had this longstanding issue with OpnSense that so far I never bothered to really check as every time I have it, I end up reverting to OpenWrt, but eventually come back, just to get frustrated with the same issue..

As the title says, after an unknown amount of time, devices lose IPv6 connectivity. The reason I say unknown is because it's between anywhere from a few minutes to a few months, I have not been able to determine any consistent reason for it happening.

What happens, based on my observations so far (and in the past with Wireshark), is that the OpnSense machine stops sending out RA packets. Devices keep their IPv6 addresses but due to no RA packets arriving anymore, the IPv6 routes (?) lose validity and IPv6 connectivity breaks.
This happens on multiple devices, ranging from my PC which runs Windows 11 (or in the past Windows 10) to phones, both Android and iOS, as well as Linux machines.

Restarting the Router Advertisement Daemon via the OpnSense WebUI does usually resume connectivity - for a (usually short) amount of time. I've tried workarounds in the past such as a cronjob to restart the RA Daemon, but in the end the connectivity was never *stable*.

What I've also observed is that I do not have this issue with any Linux-Based Router solutions (OpenWRT, VyOS), but I do have this issue on both OpnSense and pfSense. My assumption is that it has something to do with the RA Daemon used by BSD systems, but I'm not deep enough in this topic to make that conclusion or look any further without help..

Getting any help with this would be great, I really like OpnSense but if this keeps going I might have to finally move away from it for real, as it is quite frustrating to have no IPv6 connectivity :(
What logs or other data can I post/share to help figure this out?

I am on Version 24.7.11_2 by the way, and this issue has persisted since I started using OpnSense, which I think was around 19.7.