I was able to reproduce this problem with an attached debugger - looks like it needs a fairly simple fix.
Device: Onplus 3T, running Android 8, Ultimaker 3 App version 1.0.1, firmware update on the printer last done on the 20th.
12-23 18:19:51.418 10509-10509/? W/System.err: com.google.gson.JsonSyntaxException: java.lang.NumberFormatException: Expected an int but was 42115.42551996263 at line 1 column 326 path $.heads[0].extruders[0].active_material.length_remaining
12-23 18:19:51.424 10509-10509/? W/System.err: at com.google.gson.internal.bind.TypeAdapters$11.read(TypeAdapters.ja