In the past, KDEConnect would crash in these cases. Now, it no longer crashed but still won't connect reliably. The only way to resolve it is to reboot the PC (or phone, I forget which). With 1.3.5 it doesn't lose the connection as often, but it it still happens and there is no way to get the connection back. I believe it is still related to this bug: https://bugs.kde.org/show_bug.cgi?id=410316