when uploading: org.openstreetmap.josm.data.osm.DataIntegrityProblemException: Primitive cannot be modified in read-only dataset

[aseerel4c26]

What steps will reproduce the problem?

(not sure if that will always happen - but this is what I did:

0. could be (I do not remember if it was in this JOSM session) that I tried to open a saved data layer, forbid uploading, downloaded OSM data into it. ... tried to test ticket 8039 .
1. make some edits which involved a way split (which is part of several route relations) and changing the way's tags
2. upload

What is the expected result?

upload succeeds

What happens instead?

upload is partially done. Changeset is not closed ( ​https://www.openstreetmap.org/changeset/56471159 ) by JOSM. Apparently the data was uploaded correctly, though.

Please provide any additional information below. Attach a screenshot if possible.

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2018-02-18 17:20:31 +0100 (Sun, 18 Feb 2018)
Revision:13439
Build-Date:2018-02-18 17:32:43
URL:http://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (13439 de) Linux Linux
Memory Usage: 374 MB / 2048 MB (168 MB allocated, but free)
Java version: 9.0.4+11, Oracle Corporation, OpenJDK 64-Bit Server VM
VM arguments: [-Dawt.useSystemAAFontSettings=on, -Dswing.aatext=true]
Dataset consistency test: No problems found

Plugins:
+ OpeningHoursEditor (33876)
+ buildings_tools (34040)
+ measurement (33760)
+ reverter (34036)
+ terracer (33839)
+ todo (30303)
+ turnrestrictions (33780)
+ undelete (33980)
+ utilsplugin2 (33991)

Tagging presets:
+ https://raw.githubusercontent.com/OpenSeaMap/josm/master/Presets_Hafen.xml
+ https://josm.openstreetmap.de/josmfile?page=Presets/LaneAttributes&zip=1

Map paint styles:
- https://josm.openstreetmap.de/josmfile?page=Styles/Surface&style&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&style&zip=1
+ https://josm.openstreetmap.de/josmfile?page=Styles/Lane_and_Road_Attributes&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Maxspeed&zip=1
- https://josm.openstreetmap.de/josmfile?page=Styles/Coloured_Streets&zip=1

Last errors/warnings:
- E: Fehler beim Laden des Bildes 'Waypoint'
- E: Fehler beim Laden des Bildes 'Campground'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Flag'
- E: Fehler beim Laden des Bildes 'Car'
- E: Handled by bug report queue: org.openstreetmap.josm.data.osm.DataIntegrityProblemException: Primitive cannot be modified in read-only dataset: {Way id=-47494 version=0 MVT nodes=[{Node id=431153943 version=4 V lat=50.0124611,lon=8.7968209}, {Node id=431153944 version=5 V lat=50.0124722,lon=8.7992457}]}


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

Warning issued by: BugReportExceptionHandler#handleException

=== STACK TRACE ===
Thread: main-worker-0 (52)
org.openstreetmap.josm.data.osm.DataIntegrityProblemException: Primitive cannot be modified in read-only dataset: {Way id=-47494 version=0 MVT nodes=[{Node id=431153943 version=4 V lat=50.0124611,lon=8.7968209}, {Node id=431153944 version=5 V lat=50.0124722,lon=8.7992457}]}
	at org.openstreetmap.josm.data.osm.OsmPrimitive.checkDatasetNotReadOnly(OsmPrimitive.java:282)
	at org.openstreetmap.josm.data.osm.OsmPrimitive.setOsmId(OsmPrimitive.java:315)
	at org.openstreetmap.josm.io.DiffResultProcessor.postProcess(DiffResultProcessor.java:138)
	at org.openstreetmap.josm.io.OsmApi.uploadDiff(OsmApi.java:561)
	at org.openstreetmap.josm.io.OsmServerWriter.uploadChangesInChunks(OsmServerWriter.java:174)
	at org.openstreetmap.josm.io.OsmServerWriter.uploadOsm(OsmServerWriter.java:218)
	at org.openstreetmap.josm.gui.io.UploadPrimitivesTask.realRun(UploadPrimitivesTask.java:250)
	at org.openstreetmap.josm.gui.io.AsynchronousUploadPrimitivesTask.realRun(AsynchronousUploadPrimitivesTask.java:131)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.doRealRun(PleaseWaitRunnable.java:95)
	at org.openstreetmap.josm.gui.PleaseWaitRunnable.run(PleaseWaitRunnable.java:143)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
	at java.base/java.lang.Thread.run(Thread.java:844)