IllegalMonitorStateException - WalkThread

[anonymous]

What steps will reproduce the problem?

1. When starting the walk mode for Mapillary the error occured

URL:http://josm.openstreetmap.de/svn/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2017-04-02 01:45:00 +0200 (Sun, 02 Apr 2017)
Build-Date:2017-04-02 01:34:50
Revision:11826
Relative:URL: ^/trunk

Identification: JOSM/1.5 (11826 en) Windows 10 64-Bit
Memory Usage: 601 MB / 989 MB (232 MB allocated, but free)
Java version: 1.8.0_111-b14, Oracle Corporation, Java HotSpot(TM) Client VM
Screen: \Display0 1920x1080
Maximum Screen Size: 1920x1080
Dataset consistency test: No problems found

Plugins:
+ Mapillary (v1.5.0)
+ OpeningHoursEditor (33185)
+ apache-commons (32994)
+ apache-http (32699)
+ buildings_tools (33004)
+ photo_geotagging (33088)
+ photoadjust (33088)
+ terracer (33088)
+ turnrestrictions (33088)

Last errors/warnings:
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: java.io.IOException: Attribution is not loaded yet
- W: Server returned HTTP response code: 504 for URL: https://a.mapillary.com/v3/objects?client_id=T1Fzd20xZjdtR0s1VDk5OFNIOXpYdzoxNDYyOGRkYzUyYTFiMzgz&bbox=-8.592732%2C37.3150878%2C-8.5913346%2C37.3160723
- E: Handled by bug report queue: java.lang.IllegalMonitorStateException


=== REPORTED CRASH DATA ===
BugReportExceptionHandler#handleException:
No data collected.

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: Thread-135 (1073)
java.lang.IllegalMonitorStateException
	at java.lang.Object.wait(Native Method)
	at org.openstreetmap.josm.plugins.mapillary.actions.WalkThread.run(WalkThread.java:78)