u/Dear-Past5018

I replaced some outlets in my mother-in-laws house. Found these connectors that look like IDC's for low voltage in the boxes. Was this ever a thing? Is this OK? Or do I need to go through the whole house and fix this? I removed all the ones I found so far and pigtailed the wires properly. Wondering if I should go through the whole house and fix...

Seeking help from the some experienced electricians.

Thanks.