GeoServer Cluster - Malformed uxxxx encoding

I’ve setup a Basic GeoServer cluster with a Load Balancer and a shared volume between the master and slaves with Docker. I’ve also got a Python script listening on changes to the data_dir (using watchdog), which then resets and reloads the slaves on changes on master.

This setup generally works great, but sometimes, from out of the blue, this error occurs for some layers claiming to be caused by some sort of malformed encoding:

Caused by: java.lang.RuntimeException: java.lang.IllegalArgumentException: Malformed uxxxx encoding.
    at org.geowebcache.storage.blobstore.file.FileBlobStore.getLayerMetadata(FileBlobStore.java:691)
    at org.geowebcache.storage.blobstore.file.FileBlobStore.putLayerMetadata(FileBlobStore.java:647)
    at org.geowebcache.storage.blobstore.file.FileBlobStore.persistParameterMap(FileBlobStore.java:572)
    at org.geowebcache.storage.blobstore.file.FileBlobStore.writeFile(FileBlobStore.java:557)
    at org.geowebcache.storage.blobstore.file.FileBlobStore.put(FileBlobStore.java:477)
    at org.geowebcache.storage.CompositeBlobStore.lambda$put$6(CompositeBlobStore.java:182)
    at org.geowebcache.storage.CompositeBlobStore.lambda$readActionUnsafe$20(CompositeBlobStore.java:504)
    at org.geowebcache.storage.CompositeBlobStore.readFunctionUnsafe(CompositeBlobStore.java:486)
    at org.geowebcache.storage.CompositeBlobStore.readActionUnsafe(CompositeBlobStore.java:501)
    at org.geowebcache.storage.CompositeBlobStore.put(CompositeBlobStore.java:182)
    at org.geoserver.gwc.ConfigurableBlobStore.put(ConfigurableBlobStore.java:225)
    at org.geowebcache.storage.DefaultStorageBroker.put(DefaultStorageBroker.java:85)
    at org.geowebcache.layer.TileLayer.saveTiles(TileLayer.java:545)
    at org.geoserver.gwc.layer.GeoServerTileLayer.getMetatilingReponse(GeoServerTileLayer.java:654)
    ... 111 more
Caused by: java.lang.IllegalArgumentException: Malformed uxxxx encoding.
    at java.base/java.util.Properties.loadConvert(Properties.java:654)
    at java.base/java.util.Properties.load0(Properties.java:453)
    at java.base/java.util.Properties.load(Properties.java:404)
    at org.geowebcache.storage.blobstore.file.FileBlobStore.getLayerMetadata(FileBlobStore.java:689)
    ... 124 more

I can see that the metadata.properties-file for the GeoWebCache gets filled with sequences of u0000, and the sequences seems to grow larger and larger, so I’m guessing the GeoServer finally runs out of memory, because after a while I can’t request any tiles from the GeoServer.

I’ve only found one other post about this problem here: https://osgeo-org.atlassian.net/browse/GEOS-9272

Does any one know why this problem occurs and how one could fix it? I’m using GeoServer 2.17