I have now for quite some time issues with my bluetooth. It all started after the bluetooth power saving feature was introduced in Fedora 27 or 28. I do get the point of turning off the bluetooth when it is not in use, but this seems to cause a few issues on my system: my bluetooth drops what appears randomly, however it is triggered by holding down the left button of my bluetooth mouse, such as when I try to hold the scroll button in firefox, or by selecting a file in nautilus and trying to move it to another location - not always, but often enough to be a problem.

Also another issue I have is the time it takes for the bluetooth to wake-up. It takes close to 10 sec to become active again, which is quite annoying, such as when you boot into your system and want to use the mouse, but have to wait until the bluetooth is up and the device paired. This gets particularly annoying if you are in the middle of a work process and suddenly the mouse disconnects and you have to wait several seconds until it comes back to continue working. A few seconds might not sound that bad, but if you are in the middle of something and you expect or need the mouse immediately, it simply interferes with productivity.

I only have a bluetooth mouse paired to my system

bluetoothctl devices

ThinkPad Bluetooth Laser Mouse
lsusb | grep Bluetooth

Bus 001 Device 006: ID 0a5c:21e6 Broadcom Corp. BCM20702 Bluetooth 4.0 [ThinkPad]

Not sure if this is related, but I found the following entry in the dmesg log:
[ 3065.902873] hid-generic 0005:12AE:6038.0003: unknown main item tag 0x0