I have a new X70 and have the same issue.  I'm ready to pitch it out the window.  I had an X55 system that was rock stable for months and then started having the same issue about a month ago.  Nothing in my home changed.  So I thought I'd upgrade to the X70 and it's not any better, and maybe even worse.

I've been reading everything I can on the internet and many other are having the same issue, but I never have seen a clear resolution.

I just rebooted my network, now I have 22 connected items out of about 80 in my home.  I'm ready to try another brand.  I'm not sure why it is rated to highly on reviews and networking sites.

I guess I should add as above, it seems to be loT items.  TVs, iPhones and laptops don't seem to have an issue.

Try giving your IoT devices that are used in any automations a fixed IP address by entering it into the address reservation list on the XE75.