The Bluetooth applet from Plasma shows "No Devices Found" after sleep. Bluetooth works and paired devices are visible from "Configure Bluetooth" dialog. Removing then re-adding (repairing) devices makes them appear back into the applet's list, just to disappear again after putting the laptop on sleep. I'm not sure if this is a distribution-related issue, the same happens on my friend's Lenovo laptop but he's using the same distribution and Bluedevil version. Bluedevil version: 5.11.5 Bluetooth device: integrated into the Intel® Dual Band Wireless-AC 7260 (https://ark.intel.com/products/75439/Intel-Dual-Band-Wireless-AC-7260) on an Asus N751JK laptop Kernel version: 4.9.76-1-MANJARO
Same behaviour with the same Distro. After resume, I can't connect any known device if I not remove them before. Manjaro Kernel: 4.14.14 Bluedevil version: 5.11.5 Lenovo Thinkpad Laptop with Intel Corporation Wireless 8265 / 8275 (rev 78)
That's not an issue in Bluedevil as it just forwards the connection request to BlueZ. If you can reproduce the same issue when also manually calling the "org.bluez.Device1.Connect" method (eg. with qdbusviewer - Bluez is on system bus as org.bluez) then you should report this on BlueZ bugtracker.
This seems to be fixed, I'm not sure if it was a Bluedevil issue or a Manjaro one.
closing because comment 3.
Fixed for me too after upgrade to kde 5.12