Binder crashes with NullPointerException

On 0.72, adding an empty repo (repo index with no apps). No other repos enabled.

Upon updating, this happens:

D/FDroid  ( 7511): Updating/inserting 0 apks.
D/FDroid  ( 7511): Removing 0 apks from repo https://f-droid.org/repo
D/FDroid  ( 7511): Removing 0 apks from repo https://f-droid.org/archive
D/FDroid  ( 7511): Removing 0 apks that don't have any apks
D/FDroid  ( 7511): Calculating whether apps are compatible, based on whether any of their apks are compatible
D/FDroid  ( 7511): Calculating suggested versions for all apps which don't specify an upstream version code.
D/FDroid  ( 7511): Calculating suggested versions for all apps which specify an upstream version code.
D/FDroid  ( 7511): Updating icon paths for apps belonging to repos with version >= 11
D/FDroid  ( 7511): Using icon dir '/icons-480/'
W/Binder  ( 7511): Caught a RuntimeException from the binder stub implementation.
W/Binder  ( 7511): java.lang.NullPointerException
W/Binder  ( 7511):      at org.fdroid.fdroid.views.fragments.AvailableAppsFragment$CategoryObserver.onChange(AvailableAppsFragment.java:81)
W/Binder  ( 7511):      at org.fdroid.fdroid.views.fragments.AvailableAppsFragment$CategoryObserver.onChange(AvailableAppsFragment.java:93)
W/Binder  ( 7511):      at android.database.ContentObserver.dispatchChange(ContentObserver.java:163)
W/Binder  ( 7511):      at android.database.ContentObserver$Transport.onChange(ContentObserver.java:195)
W/Binder  ( 7511):      at android.database.IContentObserver$Stub.onTransact(IContentObserver.java:60)
W/Binder  ( 7511):      at android.os.Binder.execTransact(Binder.java:404)
W/Binder  ( 7511):      at dalvik.system.NativeStart.run(Native Method)
D/FDroid  ( 7511): Update took 1 seconds.
D/FDroid  ( 7511): Invalidating preference 'lastUpdateCheck'.