Something is really weird here.
[JGHGH] 14:19:37 INFO: Ready to synchronize "folder1" (folder1) (readwrite)
[JGHGH] 14:19:37 INFO: Ready to synchronize "test" (test) (readwrite)
[JGHGH] 14:19:37 INFO: Ready to synchronize "Default Folder" (default) (readwrite)
So far so good, starting up up some folders.
[JGHGH] 14:19:37 WARNING: Error on folder "folder1" (folder1): folder path missing
[JGHGH] 14:19:37 INFO: Failed initial scan of readwrite folder "folder1" (folder1)
OK, that thing doesn’t exist, but no biggie.
[JGHGH] 14:19:37 INFO: Completed initial scan of readwrite folder "test" (test)
The “test” folder is fine. 
[JGHGH] 14:19:39 INFO: Established secure connection to OGDJTJX-DVOE24J-3MNM2AQ-7EHB55U-IOFXZDG-W4ZJPMU-LWQHFZM-Z53DNAC at 192.168.1.39:51822-139.162.8.193:22000/tcp-client (TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305)
[JGHGH] 14:19:39 INFO: Device OGDJTJX-DVOE24J-3MNM2AQ-7EHB55U-IOFXZDG-W4ZJPMU-LWQHFZM-Z53DNAC client is "syncthing v0.14.48" named "syncthing1" at 192.168.1.39:51822-139.162.8.193:22000/tcp-client
[JGHGH] 14:19:39 INFO: Adding folder "test" (test)
We connected to a new device, presumably with the introducer or auto accept folders option set, and it’s announcing the folder “test”. For some reason I don’t understand we decide that we should add it again.
panic: cannot start already running folder test
Clearly, because it already exists.
There were some changes lately to how we check for folder presence and sharing. @imsodin, ideas?