Also, 2 weeks ago Last Epoch disabled family account sharing because it was being abused for real money trading:
We have unfortunately had to disable family sharing on Steam for Last Epoch.
This feature enabled the use of significant RMT (Real Money Trading) and Botting options, and was removing our ability to ban/remove accounts, faster than they could share them with their entire networks.
I don’t think any one specific thing is responsible for this change, but the 5 account limit seems like it would certainily be a welcome change for the Last Epoch devs.