I can confirm that as of the date of this post the issue persists!
My son does exactly the same.
I'm an IT engineer and here are my observatins and thoughts:
1. Xbox One doesn't have an in-built power source (aka battery or accum) like the one you can find on a typical PC motherboard. It is usually intended to provide a long-lasting power source to keep the CMOS settings (e.g. system time). That is why when the
console is unplagged from power for some time it losts some settings like time, etc. I assume it losts family account settings like limit too.
2. Once the console is plugged back and turned on it tries to connect to wifi and update various settings including time, and family account settings. (In case if they had been changed while the console was off/offline).
3. If the connection is not available at this moment (e.g. it had been purposely disconnected before the console was turned off) it probably keeps trying a few more times or some limited time (like 5 minutes mentined above) but after that it stops trying
and NEVER tries again. So if the settings including the limites have not been provided/updated during the start process they won't be requested again after even if wifi connection is restored and available.
Microsoft, this is a MASSIVE issue that must be fixed!
The information about such loopholes gets spread across by teendage folks REALLY quickly - go on YouTube and check. It devaluates the whole idea of family accounts and control!